The impact of body mass index on semen parameters in infertile men

This hospital‐based, prospective study was conducted to evaluate the relationship between body mass index (BMI) and various semen parameters in infertile men. A total of 439 men presented for infertility evaluation were assessed by basic infertility evaluation measures including semen analysis and BMI calculation. The main outcome measure was the relationship between BMI groups [BMI: 18.5–24.9 kg/m² (normal weight), 25–29.9 kg/m² (overweight) and ≥30 kg/m² (obese)] and different semen parameters [volume, concentration, motility and morphology]. The mean BMI was 29.67 ± 5.89. Most of patients (82.91%) were overweight or obese. The 3 BMI groups were comparable in semen parameters (P > 0.05). BMI had a negative correlation with various semen parameters. However, this correlation was significant only with sperm concentration (P = 0.035). We concluded that sperm concentration was the only semen parameter which showed significant reduction with higher BMI in infertile men.     

The effects of bacterial infection on human sperm nuclear protamine P1/P2 ratio and DNA integrity

The purpose of this study was to detect the effects of bacterial infection on human sperm nuclear protamines and DNA fragmentation. In this study, 120 semen samples were collected from unselected male partners of couples consulting for infertility in infertility and obstetrics clinic. All the samples were screened bacteriologically according to World Health Organization guidelines, and also sperm parameters and DNA fragmentation were evaluated. The concentrations of protamines P1 and P2 were quantified using acid urea acrylamide gel electrophoresis. Of a total number of 120 sample, 36 (30%) of them were infected with bacteria. Nine species of bacteria belonging to five genera, Staphylococcus, Escherichia, Streptococcus, Enterococcus and Klebsiella, were identified. The comparison between infected (36) and noninfected (84) samples appeared the negative impact of bacterial infection on sperm parameters and P1/P2 ratios. The percentages of P1/P2 ratio abnormality were significantly higher in infected patients. Sperm concentration, motility, progression and chromatin condensation were significantly lower in infected patients (p < .010). Depending on these results, we concluded that the bacterial infections have significant negative effects on sperm chromatin condensation and protamine P1/P2 ratio. Moreover, the negative relationship between the bacterial infections and sperm parameters, such as concentration, motility and progressive motility, has been shown.     

Fertility of Spinal Cord Injured Males: Effect of Genitourinary Infection and Bladder Management on Results of Electroejaculation

ABSTRACT

Thirty-eight men undergoing electroejaculation (EEJ) procedures for anejaculatory infertility were examined for the presence or absence of infection in urine and semen. In 29 spinal cord injury patients, a high incidence of infected urine and infected semen (41% and 56%, respectively) was seen, in contrast to patients with normal bladder function (0% and 11 %).

Urinary infection was associated with slightly lower sperm quality and lower pregnancy rates (10% vs 30% in the presence of sterile urine). Semen infection had no effect on sperm counts or pregnancy rates. If intermittent self-catheterization (ISC) was used to empty the neurogenic bladder, slightly better sperm quality was seen, the total failure rate was less, and much better pregnancy rates (44%) resulted than for patients using an alternative bladder management (7%).

Antibiotics did not reduce the incidence of urine or semen infection, but did improve sperm counts slightly. Continuous prophylaxis was associated with bacterial resistance to many oral antibiotics and had no advantage over a short course of antibiotics prior to the procedure.

Despite the above associations, the sperm quality in our patient population was never normal compared with that of men who ejaculate normally. We conclude that the low sperm quality seen in electroejaculation specimens from spinal cord injured males is not due entirely to infection or to the type of bladder management. Short courses of antibiotics, instead of continuous antibiotic prophylaxis, may be beneficial. Intermittent catheterization is superior to other methods of neurogenic bladder management in maintaining the fertility of spinal cord injured men.     

The micronutrient supplements,zinc sulphate and folic acid,did not ameliorate sperm functional parameters in oligoasthenoteratozoospermic men

We investigated the effects of folic acid and zinc sulphate supplementation on the improvement of sperm function in subfertile oligoasthenoteratozoospermic (OAT) men. Eighty‐three OAT men participated in a 16‐week intervention randomised, double‐blind clinical trial with daily treatment of folic acid (5 mg day^?1) and zinc sulphate (220 mg day^?1), or placebo. Before and after treatment, semen and blood samples were obtained for determining sperm concentration, motility, and morphology, sperm viability, sperm mitochondrial function, sperm chromatin status using toluidine blue, aniline blue, acridine orange and chromomycin A₃ staining; and semen and blood folate, zinc, B₁₂, total antioxidant capacity ( TAC) and malondialdehyde (MDA) concentrations. Sperm concentration (×10⁶ ml^?1) increased in subfertile men receiving the combined treatment of folic acid and zinc sulphate and also in the group receiving only folic acid treatment; however, it was not statistically significant (P = 0.056 and P = 0.05, respectively). Sperm chromatin integrity (%) increased significantly in subfertile men receiving only zinc sulphate treatment (P = 0.048). However, this improvement in sperm quality was not significant after adjusting placebo effect. This study showed that zinc sulphate and folic acid supplementation did not ameliorate sperm quality in infertile men with severely compromised sperm parameters, OAT. Male infertility is a multifactorial disorder, and also nutritional factors play an important role in results of administration of supplementation on sperm parameters. However, these results should be confirmed by multiple studies in larger populations of OAT men.     

Hypoxia pathway has more impact than inflammation pathway on etiology of infertile men with varicocele

This study aimed to compare main molecular markers of hypoxia (HIF1‐α and P53) and inflammation (TLR‐2, TLR‐4 and TNF‐α) pathways between infertile men with varicocele and fertile individuals. Sperm parameters such as sperm concentration, motility and morphology were assessed according to World Health Organization (Laboratory manual for the examination and processing of human semen. Geneva, Switzerland, 2010) guideline in 20 infertile men with grade II or III varicocele, and 20 fertile men candidate of family balancing. In addition, sperm DNA fragmentation and molecular markers involved in hypoxia and inflammation pathways were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay and real‐time PCR respectively. Mean of sperm parameters (concentration, motility and morphology) and DNA integrity were significantly lower in infertile men with varicocele compared to fertile individuals. Unlike markers involved in inflammation pathway, mean expression of markers of hypoxia pathway (HIF1‐α and P53) was significantly higher in infertile men with varicocele compared to fertile individuals (p < 0.05), and also a significant correlation was observed between expression of HIF1‐α and P53 (r = 0.461; p = 0.003). Overall, the result of this study suggests higher likelihood of involvement of hypoxia pathway, in comparison with inflammation pathway, in pathogenesis varicocele associated with male infertility.     

Effects of microsurgical varicocelectomy on semen analysis and sperm function tests in patients with different grades of varicocele: Role of sperm functional tests in evaluation of treatments outcome

It seems that varicocele play a role in male infertility, as such, their prevalence increases from 15% in the normal population to 80% in secondary infertility subjects. Varicoceles may have negative effects on semen quality. Our goal was to assess the effects of microsurgical varicocelectomy on semen analysis and sperm functional tests in men with different grades of varicoceles. Thirty infertile men with different grades of varicoceles (grades 1 to 3) were enrolled in our study. Semen quality was assessed by semen analysis according to the WHO guideline (WHO, 1999) and four different sperm functional tests (aniline blue, toluidine blue, chromomycin A3 and TUNEL test) were carried out before and 3 months after microsurgical varicocelectomy (M‐varicocelectomy). When considered all three grades together, we showed that M‐varicocelectomy had statistically significant effects on all four types of sperm functional tests (p value<0.05). It also had positive effects on conventional semen parameters, although the effects were not statistically significant for some parameters (for example sperm count). When analysed separately (based on varicocele grades) the surgery, although caused improvements in semen quality, but may have more statistically significant effects on patients with varicocele of higher grade. In addition, in varicocele of lower grade (for example grade 2), sperm function test may be a better predictor of surgical success than the conventional semen analysis. Thus, we show that not only M‐varicocelectomy has significant positive effect on semen quality but also if sperm functional tests become more affordable in the future, because they yield more precise results, their use in daily practice may increase significantly in patients with varicoceles.     

Association of asymptomatic Chlamydia trachomatis infection with male infertility and the effect of antibiotic therapy in improvement of semen quality in infected infertile men

The role of asymptomatic infections caused by Chlamydia trachomatis in male infertility and the efficacy of antibiotics in the treatment of this condition are not yet definitely determined. A total of 165 infertile males having abnormal semen parameters (study group) as well as 165 healthy fertile men (control group) were included. Semen samples were taken from all participants and after analysing for semen parameters, undergone real‐time PCR, and reactive oxygen species (ROS) as well as total antioxidant capacity (TAC) assays. Infected individuals of study group were treated with antibiotic. One month after the treatment completion, second semen samples were taken and undergone all the tests mentioned. The frequency of C. trachomatis was significantly higher in the infertile men compared with the fertile ones (4.2% vs 0.6%). Most of the semen parameters were improved and reached their normal range, the level of TAC elevated and ROS level as well as ROS/TAC ratio reduced after antibiotic treatment. Moreover, wives of three infected infertile men (42.9%) became pregnant 4 months after the treatment completion. Our data suggest that asymptomatic infection caused by C. trachomatis is correlated with male infertility and antibiotic therapy can improve the semen quality and fairly treat the male infertility.     

Semen quality over a 10-year period in 22,249 men in Korea

A retrospective study was conducted in a large population presenting with infertility to determine whether sperm quality has changed in Korea in the last 10 years. We reviewed sperm concentration, motility and semen volume in 22,249 men from whom semen was collected in our laboratory between January 1989 and April 1998 and analysed according to WHO (1987) guidelines. Mean age of the men was 32 years (range 21-40). Data were collected in healthy men with infertility. The mean sperm concentration was 60.5 x 10(6)/mL from 1989 to 1998. There was no statistically significant difference for each year (p > 0.05). Semen volume and sperm motility were also unchanged during the same time period. There was no significant association between either age or year of birth and semen quality. Of the total population, 4033 men (19.0%) exhibited azoospermia and 8397 men (40. 1%) had normal semen parameters which satisfied the 1987 WHO criteria. The changes observed in the semen parameters analysed in this large population showed no evidence of deteriorating semen quality in Korea over the last 10 years.     

Normal sperm parameters per se do not reliably account for fertility: A case–control study in the real-life setting

A proportion of men are infertile despite having normal medical history/physical examination and normal semen analysis. We aimed to assess whether normal sperm parameters per se account for male factor fertility. 1,957 infertile men were compared with 103 age-comparable fertile controls. Semen analysis was based on 2010 World Health Organization reference criteria. Of all, 12.1% of infertile men and 40.8% of fertile men presented with normal sperm parameters. Among fertile men, 36.9% had isolated sperm abnormalities and 22.3% men showed two or more concomitant sperm abnormalities. Serum total testosterone was higher in infertile men with normal sperm parameters compared to those with ≥2 sperm abnormalities or azoospermia, but similar to those with isolated sperm abnormalities (p ≤ .001). Circulating hormones were similar among sperm parameters groups in fertile men. At multivariable analyses, testicular volume (OR 1.12, p ≤ .001) and FSH (OR 0.8, p ≤ .001) were associated with normal sperm parameters. Overall, the longer the infertility period, the greater the number of sperm parameters abnormalities (p < .01). In conclusion, we found that 12% of infertile men and only 41% of fertile men present with normal sperm parameters. Normal sperm parameters per se do not reliably account for fertility in the real-life setting.     

精浆弹性蛋白酶水平与精液主要参数和精子功能的相关性分析

目的:探讨精浆弹性蛋白酶与精液主要参数和指标的关系。方法:用酶联免疫吸附法(ELISA)检测精浆中的弹性蛋白酶,按照WHO人类精液实验室手册要求进行精液常规分析、精子形态分析,检测精子顶体酶活性、精浆抗体(AsAb)、解脲支原体等,分析弹性蛋白酶与男性不育相关因素的关系。结果:209例男性不育患者中,43例患者精浆弹性蛋白酶≥290ng/ml,设为炎症组;166例患者精浆弹性蛋白酶<290ng/ml,设为非炎症组。炎症组的精子密度、精子活动率、a+b级活力精子率、精子顶体酶阳性率均低于非炎症组(P<0.05);而精子畸形率、精浆抗体(AsAb)、解脲支原体阳性率均高于非炎症组(P<0.05)。两组的精液量、PH值和液化时间差异无统计学意义。结论:精浆弹性蛋白酶水平与精液质量有密切的关系,生殖道感染是导致男性不育的重要原因。     

Diagnostics of DNA fragmentation in human spermatozoa: Are sperm chromatin structure analysis and sperm chromatin dispersion tests (SCD‐HaloSpermG2®) comparable?

Men affected with idiopathic infertility often display basic spermiogramme values similar to fertile individuals, questioning the diagnostic impact of the World Health Organization (WHO) thresholds used. This study explored sperm DNA fragmentation in single ejaculates from 14 fertile donors and 42 patients with idiopathic infertility providing semen for assisted reproductive techniques in a university fertility clinic. Each ejaculate was simultaneously studied for sperm DNA fragmentation by the flow cytometer‐based sperm chromatin structure analysis (SCSA) and the new light‐microscopy‐based sperm chromatin dispersion assay (SCD‐HaloSpermG2^®), before and after sperm selection for in vitro fertilisation with a colloid discontinuous gradient. The WHO semen variables did not differ between groups, but DNA fragmentation after SCSA (DFI) or SCD (SDF) was significantly (p < 0.05) higher in patients (DFI: 40.2% ± 3.0 vs. SDF: 40.3% ± 1.4) than in fertile donors (DFI: 17.1% ± 2.1 vs. SDF: 20.9% ± 2.5). Sperm selection led to lower proportions of DNA‐fragmented spermatozoa (DFI: 11.9 ± 1.7 vs. SCD: 10.0 ± 0.9, p < 0.05). The techniques output correlated highly and significantly (r² = 0.82). DNA fragmentation is confirmed as a relevant variable for scrutinising patients with idiopathic infertility, beyond the evidently insufficient WHO semen analyses. Since both techniques yielded similar results, the reduced necessity of complex equipment when running SCD ought to be considered for a clinical setting.     

精液粘度与精液分析参数、解脲支原体感染和抗精子抗体关系分析

目的探讨精液粘度增高导致男性不育的机理。方法共4337例不育门诊就诊者,分为精液粘度增高和正常组,观察粘度与主要精液常规参数、UU感染率和AsAb阳性率关系。结果精液粘度增高率为65.02%。粘度增高组精子活动率、a,b级活力精子率显著低于粘度正常组(P<0.05,P<0.001);畸形精子率、液化时间均明显高于粘度正常组(P<0.001);两组精液量、精子密度和精液pH比较无显著性差异(P>0.05)。精液白细胞>5个/HP组粘度增高率明显高于白细胞<5个/HP组(P<0.001)。粘度增高组精浆AsAb阳性率和精液UU阳性率均明显高于粘度正常组(P<0.001)。结论精液粘度可影响精液参数,并与精液白细胞数、精浆AsAb和UU感染有关。     

A randomised trial comparing conventional semen parameters,sperm DNA fragmentation levels and satisfaction levels between semen collection at home and at the clinic

The aim of the randomised trial was to compare conventional semen parameters, sperm DNA fragmentation levels and satisfaction levels between semen samples collected at home and at the clinic. We recruited 110 men with a history of infertility for at least 1 year from the outpatient andrology clinic. Each man collected two semen samples, one at home and one at the clinic. Men were randomly assigned into the home first (n = 55) or clinic first (n = 55) groups. The primary outcome was sperm concentration. There was no significant difference in sperm concentration, sperm DNA fragmentation levels or other conventional semen parameters between home first and clinic first samples (p > .05), while satisfaction levels were significantly higher for home first samples (p < .01). Consistent results were obtained when comparing home-collected and clinic-collected samples within individuals. Men can be offered the option to collect semen samples at home for examination or assisted reproduction without compromising semen quality, especially for those with difficulty in producing semen samples at the clinic.     

Role of antioxidants in the treatment of male infertility

Male infertility continues to be a clinical challenge of increasing significance. While male factors such as decreased semen quality are responsible for 25% of all infertility issues, the etiology of suboptimal semen quality is poorly understood. Many physiological, environmental, and genetic factors have been implicated, including oxidative stress. Oxidative stress is induced by reactive oxygen species (ROS), or free radicals, and although ROS are required for critical aspects of sperm function, excessive levels of ROS can negatively impact sperm quality. The origin of ROS generation, and the etiologies of increased ROS in men with suboptimal sperm quality have only recently been elucidated, offering multiple targets for potential therapy. Here, we present a critical review of the literature describing the role of oxidative stress on decreased sperm function, as well as the role of antioxidants in the treatment of male factor infertility.     

中国乙型肝炎和非肝炎男性间的精液质量和辅助生殖技术治疗结果的比较

本研究旨在确定乙型肝炎病毒（HBV）感染对精子质量和辅助生殖技术治疗结局的影响。分析2008年1月至2009年12月于浙江大学附属妇产科医院寻求辅助生育治疗的916例男性（457例乙型肝炎病毒携带者和459例阴性对照男性）的精液参数;将2004年1月至2009年12月期间的男性乙肝病毒携带的587个常规体外受精（In vitro fertilisation,IVF）周期和325个单精子卵细胞浆内注射（Intracytoplasmic sperm injection,ICSI）周期作为阳性观察组,根据取卵日期、女方年龄及ART受精方式通过统计软件以1：1比例匹配,设立夫妇双方均为HBsAg阴性的对照组（587个IVF周期,324个ICSI周期）,分析两组间的辅助生殖治疗结局。与对照组相比,乙肝携带者表现有较低的精液体积、精子总数以及较差的精子活动力和形态学表现（P〈0．05）;乙肝男性夫妇接受ICSI治疗后,双原核（2PN）受精率、优质胚胎率、胚胎着床率以及临床妊娠率均显著性降低俨〈0．05）;而两组病人间的IVF治疗结局差异无显著性（P〉0．05）。通过Logistic回归分析发现乙肝病毒感染作为一个独立的因素增加少弱精子症的发生以及降低ICSI治疗周期的胚胎着床率和临床妊娠率（P〈0．05）。我们的研究结果提示了男性乙型肝炎病毒感染与较差的精子质量和ICSI治疗结局有关,而对IVF治疗结局没有明显的影响。     

4977‐bp mitochondrial DNA deletion in infertile patients with varicocele

Varicocele is the abnormal inflexion and distension of veins of the pampiniform plexus within spermatic cord and is one of the amendable causes of male infertility. It can increase reactive oxygen species (ROS) production in semen and cause oxidative stress. The purpose of this study was to analyse spermatozoa mtDNA 4977‐bp deletion in infertile men with varicocele. To detect 4977‐bp deletion in spermatozoa mtDNA, semen samples of 60 infertile patients with clinical varicocele and 90 normal men from northern Iran were prepared. After extraction of spermatozoa total DNA, Gap polymerase chain reaction (Gap PCR) was performed. 4977‐bp deletion was observed in 81.66% of patients with varicocele, while approximately 15.55% of controls had this deletion. As spermatozoa from patients with varicocele had a high frequency of occurrence of 4977‐bp deletion in mtDNA [OR = 24.18, 95% confidence interval (CI) = 10.15–57.57, P < 0.0001], varicocele may induce mtDNA deletion in spermatozoa and cause infertility in north Iranian men. However, to determine the relation between sperm mtDNA 4977‐bp deletion and varicocele‐induced infertility, larger population‐based studies are needed. It is concluded that there is an association between sperm mtDNA 4977‐bp deletion and varicocele‐induced infertility in the population studied.     

Semen analysis and treatment risk factors in long-term survivors of childhood cancer

The objective of this study was to compare semen quality (sperm density, progressive motility and spermia) between long-term childhood cancer survivors and a control group of males. The second objective was to correlate the semen analysis of the survivors with cancer treatment and endocrine status. The semen quality of 143 survivors (median age, 23.6 years) was compared to 200 men (median age, 27.9 years) who had not been diagnosed with cancer. The cancer-related risk factors and gonadotrophin levels were compared. Overall, 65% of the survivors had abnormal semen analysis compared to 26.5% of the controls (p < 0.0001). Survivors with nonaspermia had lower sperm density than the controls (p < 0.001). Other observed correlations were not significant. Survivors who were treated with alkylating agents were more likely to have abnormal semen analysis (p < 0.008). Follicle-stimulating hormone and luteinising hormone levels were significantly elevated (p < 0.0001) in survivors with abnormal semen analysis. The semen quality parameters, except for low sperm density, did not differ in survivors with nonaspermia compared to the controls. The risk factors included treatment with alkylating agents. Elevated gonadotrophin levels correlated with abnormal semen analysis. All cancer survivors should be made aware of the possibility of suffering from cancer treatment-related infertility.     

精子凋亡与男性不育关系初探

目的 :探讨精子凋亡与男性不育的关系。　方法 :应用流式细胞术 (FCM)检测正常生育与不育男性精液中精子凋亡情况。　结果 :在不同人群中精子凋亡均有一定的发生率 ,生育组凋亡率 (PAS)为 (4 2 8± 1 6 6 ) % ,不育组为 (18 6 7± 8 5 5 ) % ,两者差异极显著 (P <0 .0 1) ,且PAS与精液量、精子密度、精子前向运动率、精子正常形态率呈显著负相关 (P <0 .0 1)。　结论 :精子凋亡与男性不育有着十分密切的关系 ,FCM检测精子凋亡是一种迅速、准确、客观、可靠的评估精子功能和男性生育力的新方法     

In vitro sperm-binding assay to distinguish differences in populations of human sperm or damage to sperm resulting from cryopreservation.

Annually, >1.3 million men are members of couples seeking help because of infertility. Semen from many of these men contains reasonable numbers of motile and normal sperm, but for a subset of individuals, many sperm are deficient in ability to bind to the zona pellucida during in vitro fertilization. Diagnosis of this defect has been hampered by lack of a low-cost test. Molecular similarity exists between the perivitelline membrane of a hen's egg and the mammalian zona pellucida. These facts and some preliminary data led to evaluation of binding of human sperm during incubation for 60 minutes at 37 degrees C to an extract of chicken perivitelline membrane coated in microwell assay plates. The sperm-binding assay had inter- and intraassay plate variations of 21 and 12%, respectively, using washed fresh sperm. All seminal samples were normal, except a few that had 36 to 50% motile sperm with a low rate of sperm movement (if there is a low rate of movement, World Health Organization [WHO] criterion for normalcy is >50% motile). Nevertheless, this sperm-binding assay detected differences among individuals in percentage of sperm bound. Based on data for two to four ejaculates from each of eight occasional sperm donors, the coefficient of variation for ejaculates within donor averaged 31%, and means for the donors differed (P < 0.02). Percentage of sperm bound ranged from <1 to 38% for fresh semen from 57 men and from <1 to 13% for frozen-thawed semen from 34 men. Percentage of motile sperm accounted for <30% of the variation in percentage of sperm bound. In a direct comparison based on 17 ejaculates, aliquots evaluated fresh averaged 13% sperm bound, versus 2% for frozen-thawed aliquots. We concluded that the egg membrane substrate used in these microwell assay plates might serve as the basis for a diagnostic assay. However, it remains to be established whether samples of human semen with a low percentage of sperm binding indeed have relatively low fertilizing potential.     

Flow cytometric measurement of sperm nuclear DNA fragmentation in infertile men with normal standard sperm parameters

BackgroundMale-factor infertility plays a role in approximately 50% of infertile couples. In at least 30% of cases, repeated standard semen analyses of the male partner of an infertile couple reveal normal results. When diagnostic work-up of the female partner is also normal, they are classified as idiopathic. The objective of this study was to evaluate the levels of sperm nuclear DNA fragmentation in a population of infertile men with normal standard semen parameters and to compare their results with those from men who had abnormal semen parameters, as well as with a control group of fertile men.MethodsSemen samples were obtained from 202 infertile men and 30 fertile donors. Standard semen analysis was performed according to the World Health Organization guidelines. Flow cytometry has been extensively used to study sperm DNA fragmentation and the results are expressed as the percentage of sperm DNA fragmentation index (DFI).ResultsOf the 202 patients, 48 (23.8%) had normal standard sperm parameters, while 154 (76.2%) had an abnormality in one or more of these parameters. DFI in infertile men with normal sperm parameters was significantly higher than in fertile donors (p = 0.03), but not significantly different from infertile men with abnormal sperm parameters (p = 0.10). There were statistically significant negative correlations between DFI and the percentage of motile sperm from infertile men with abnormal and normal semen parameters, but not in fertile donors (r = ?0.26, p = 0.001 and r = ?0.48, p = 0.0001, respectively).ConclusionSperm from infertile men with normal standard sperm parameters may have significant levels of DNA fragmentation that are comparable to levels in infertile men with abnormal sperm parameters. Sperm DNA fragmentation analysis is an independent test of sperm quality and has an important diagnostic value in the evaluation of male infertility.