• Question: how do male and female grow diffrent ways if we are all human

    Asked by 582xygg38 to Roisin, Michel on 7 Nov 2016.
    • Photo: Michel Destrade

      Michel Destrade answered on 7 Nov 2016:

      I think it has to do with chromosomes at the start of life (chromosomes are tiny packages full of information telling the cells how to divide and reproduce). Humans have 23 chromosomes plus the X/Y chromosome. At the very beginning of life in the mother’s uterus, the foetus has either the XX pair or the XY pair. From that tiny difference, you grow up into a girl (XX) or a boy (XY).

      Of course, I’m talking in general here. It can happen that this process plays out a little bit differently for certain people. They might have an extra X or two, or one less, and then it’s harder to define a gender in those cases.

    • Photo: Roisin Jones

      Roisin Jones answered on 8 Nov 2016:

      Think Michel has this one pretty much covered! The only thing I’d add is that the chromosomes he mentioned determine the types of hormones that will be released into our body, so for boys, when they hit puberty, their Y chromosome directs the body to release loads of testosterone, which means they gain more muscle mass, heavier bone structure, more body hair and their male genitals grow. For girls, when they hit puberty, their combination of two X chromosomes direct their bodies to release oestrogen and progesterone which leads to a higher percentage body fat (particularly in the development of breasts), less body hair than boys (and what’s there is usually finer), wider pelvic bones, and their wombs start producing eggs, starting the menstrual cycle. If you’re deficient in a certain hormone (or produce too much of it), it can have bad effects, or might mean that your body doesn’t develop in the way you expect, but this can usually be treated! Hope this answers your question. 🙂