Sexes of affected cases in sibships containing two or more members with anencephaly or spina bifida.

A study has been made of the sexes of the affected within sibships containing two or more members with anencephaly or spina bifida (ASB). There is no clear evidence for variation between ASB-prone women in their propensity to bear affected cases of one sex rather than the other. It is suggested that the point should be regarded as open until further data have settled the issue.