• Question: Why Is There a Girl And A Boy Cant It Just Be One Specific Gender?

    Asked by issi2001 to Anil, Blanka, Cees, Emma, Mike on 29 Jun 2012. This question was also asked by whstephanie, whchloep.
    • Photo: Emma Trantham

      Emma Trantham answered on 29 Jun 2012:

      That’s a really good question and really quite complex.

      Part of the answer must be because the different genders do different things – so we have evolved that it is always the female that carries the baby. This means that her body processes need to be a bit different from the males’ (although this is dependent on which animal species you are!)

      Another part of the answer must be because we reproduce sexually, that is it takes the DNA from two people to combine to produce a baby. (This is unlike microbes like bacteria which can just clone themselves.) I guess in the process of evolving sexual reproduction it developed so that an egg must always be fused with a sperm cell and that two eggs can’t combine, nor can two sperm cells.

      As soon as that sort of process developed you needed a way to tell the genders apart. So say there was a female organism – she needs to know what is male and what is female so she mates with the right organism! And so having obvious differences in the genders would be of real help.

      But appearance gender differences probably developed before our language developed – now I’m not sure there is a real need for our genders to be quite so obvious because we could just ask each other.

      I wonder if one of the other scientists knows any more?

    • Photo: Michael Cook

      Michael Cook answered on 29 Jun 2012:

      I was asking some scientists this a month or two ago, funnily enough!

      One of the other things they mentioned was something called ‘genetic diversity’. As Emma said, humans reproduce through sexual reproduction. This combines the DNA of two people together to produce a new set of genes for the baby. By combining sets of genes from two parents you get more variation in the children that are born than if we only needed on parent, like a bacterium. More variation helps a species evolve!

      Like Emma said, though, perhaps that isn’t as important to us nowadays!

    • Photo: Blanka Sengerova

      Blanka Sengerova answered on 29 Jun 2012:

      Actually it turns out that whilst humans reproduce sexually by mating of individuals of the opposite sex, there are some organisms which are hermaphrodites, meaning that they contain the sex organs of both sexes and can therefore reproduce by themselves. Although this is quite a simplified way of explaning this, but maybe it might be an interesting point to know about.

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