• Question: Why do men have nipples?

    Asked by Lesley Chow to Deborah, Euan, Maheen, Rob, Stu on 20 Jun 2016.
    • Photo: Deborah Prunty

      Deborah Prunty answered on 20 Jun 2016:

      For the first few weeks of development embryos all follow the female blueprint. The y chromosome kicks in for male after some of the development has already occurred. This includes nipples. The y chromosome stops them developing into breasts.

    • Photo: Maheen Siddiqui

      Maheen Siddiqui answered on 21 Jun 2016:

      Hi Michael Angollie,

      Thanks for the interesting question, I had never though of it myself!
      As Deborah said, for the first several weeks a developing embryo follows a “female blueprint,” from reproductive organs to nipples.

      After around 60 day the hormone testosterone kicks in (for those of those with a Y chromosome, i.e. males), changing the genetic activity of cells in the genitals and brain.

Comments