X-chromosome dosage affects male sexual behavior

Paul J. Bonthuis, Kimberly H. Cox, Emilie F. Rissman

Research output: Contribution to journalArticlepeer-review


Sex differences in the brain and behavior are primarily attributed to dichotomous androgen exposure between males and females during neonatal development, as well as adult responses to gonadal hormones. Here we tested an alternative hypothesis and asked if sex chromosome complement influences male copulatory behavior, a standard behavior for studies of sexual differentiation. We used two mouse models with non-canonical associations between chromosomal and gonadal sex. In both models, we found evidence for sex chromosome complement as an important factor regulating sex differences in the expression of masculine sexual behavior. Counter intuitively, males with two X-chromosomes were faster to ejaculate and display more ejaculations than males with a single X. Moreover, mice of both sexes with two X-chromosomes displayed increased frequencies of mounts and thrusts. We speculate that expression levels of a yet to be discovered gene(s) on the X-chromosome may affect sexual behavior in mice and perhaps in other mammals.

Original languageEnglish (US)
Pages (from-to)565-572
Number of pages8
JournalHormones and Behavior
Issue number4
StatePublished - Apr 2012
Externally publishedYes


  • Aneuploid
  • Klinefelter's Syndrome
  • Masculine behavior
  • Sex Chromosomes
  • Sexual differentiation

ASJC Scopus subject areas

  • Endocrinology
  • Endocrine and Autonomic Systems
  • Behavioral Neuroscience


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