Cord Blood Androgen Levels Of Females From Same Sex And Opposite Sex Twins - A Pilot Study

Objective Opposite-sex twins have shown behavioural and reproductive differences between females and males. These differences may be determined by higher intrauterine levels of androgens among females that were exposed to a male co-twin. The aim of this study was to compare cord blood androgen levels in females from same-sex and opposite-sex twins.Design A prospective study. In this pilot study, we compared cord blood androgens (DHEA-S, Delta-4 androstenedione, total testosterone-TT) and sex hormone-binding globulin (SHBG) levels in 20 females from same sex and 20 females from opposite-sex dichorionic diamniotic twins. We used generalized estimating equation (GEE) modelling to assess differences in cord blood androgens between females from same-sex twin pregnancies and females from opposite-sex twin pregnancies.Patients Twenty opposite-sex twin pairs (female-male twins) and 20 same-sex twin pairs (female-female).Measurements Cord blood total testosterone, Delta-4 androstenedione, DHEA-S and sex hormone-binding globulin (SHBG) levels.Results No difference in the levels of androgens as Delta-4 androstenedione, total testosterone and SHBG was identified between females that were exposed to a female co-twin compared with females that were exposed to a male co-twin. DHEA-S levels were significantly lower among females from opposite-sex twins compared with females from same-sex twins.Conclusions Our preliminary data do not support the hypothesis that females exposed to male co-twins are exposed to higher levels of androgens in utero compared with females exposed to female co-twins. Further studies are needed to explain the reported behavioural and reproductive differences among opposite-sex twins.