Heterochromatic chromosome variation and reproductive failure

The literature on the association of heterochromatic chromosome variants and reproductive failure, manifesting as infertility or recurrent spontaneous abortion, is critically reviewed. Many methodological problems confound attempts to interpret the data. The weight of evidence is against autosomal variants having any significant effect. Although conflicting, reports on the effect of Y heterochromatin variants on both infertility (Yq-) and recurrent abortion (Yq+) are mainly positive, and further data are required in both these areas.