单绒毛膜双胎的性别比例。

The sex ratio of monoamniotic twin pairs.

作者信息

James W H

出版信息

Ann Hum Biol. 1977 Mar;4(2):143-53. doi: 10.1080/03014467700002031.

DOI:10.1080/03014467700002031

Abstract

Data on more than 300 monoamniotic twin pairs have been reviewed. The sec ratios (proportions of males) and of malformed monoamniotic twins seem to be lower than that of all monozygotic twins as a whole. The sex ratio of acardiac monsters (which are all members of monochorionic monozygotic twins) seems to be lower than that of monozygotic twins as a whole. Taken in conjunction, these two pieces of evidence suggest that monochorionic monozygotic twins have a lower sex ratio than dichorionic monozygotic twins. It is argued that this is evidence for the hypothesis that the sex of a zygote is associated with the time within the menstrual cycle that it is formed.

摘要

对300多对单羊膜囊双胎的数据进行了回顾。单羊膜囊双胎的性别比（男性比例）和畸形单羊膜囊双胎的性别比似乎低于所有单卵双胎的总体水平。无心畸胎（均为单绒毛膜单卵双胎）的性别比似乎低于单卵双胎的总体水平。综合来看，这两条证据表明单绒毛膜单卵双胎的性别比低于双绒毛膜单卵双胎。有人认为，这是支持受精卵性别与月经周期内形成时间相关这一假说的证据。