Cord blood androgen levels of females from same sex and opposite sex twins – A pilot study

Valentina Galiano, Giulia Solazzo, Jaron Rabinovici, Farzam Nahid, Hemi Rina, Andrea A. Baccarelli, Ronit Machtinger*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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, Δ-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, Δ-4 androstenedione, DHEA-S and sex hormone-binding globulin (SHBG) levels. Results: No difference in the levels of androgens as Δ-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.

Original languageEnglish
Pages (from-to)85-89
Number of pages5
JournalClinical Endocrinology
Issue number1
StatePublished - Jan 2021


FundersFunder number
Environmental and Health Fund, Israel


    • androgens
    • cord blood hormones
    • females
    • intrauterine environment
    • opposite-sex twins
    • same-sex twins
    • testosterone transfer theory


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