Gender and Sex: Biology

Posted by on Jun 16, 2013 in Blog: Doing sex God’s way

Gender and Sex: Biology

Genesis 1:27 “So God created mankind in his own image, in the image of God he created them; male and female he created them.”

Caster Semenya: A female 800 metre athlete extraordinary from Africa – a Silver medallist at the Olympics 2012.

The newspaper’s reported that she has no ovaries or uterus (womb). Instead, they tell us she has undescended testis and three times the amount of testosterone that a “normal” female would have. Although not described, we can work out that she had female external genitalia and identified as a female. She had a female brain. So outwardly she looked like a female, identified as one and acted as one.

And as for her chromosomes – we are not told. Is she an XX female? Or is she a XY male?

“Semenya is a hermaphrodite” the paper’s reported.  But they got that WRONG. A true hermaphrodite has BOTH testis and ovarian tissue. Caster has testes but no ovarian tissue.

To understand what Caster Semenya is going through, we need to understand the biological foundation of being a male or female

1. Chromosomal Sex: An ovum (female egg) always carries an “X” chromosome. A sperm could carry either a “X” or a “Y”. When a sperm and ovum meet, an XY sex chromosome combination determines a BOY baby and an XX combination a GIRL baby. Sometimes things get messed up right here, with  XO (Turners Syndrome), XXY (Klinefelters) and other genetic errors.

2. Gonadal Sex: In the presence of a “Y” chromosome (an XY combination) – we have testis develop.  Else an ovary. Rarely we have bits of both – Hermaphroditism. Once the testis starts developing – it produces the male hormone Testosterone.

3. Genital Sex: Testosterone now starts ‘masculinising’ the internal and external genitalia.  This happens about 6-7 weeks after fertilisation of the ovum by the sperm.  If there is no testosterone (as in a female baby) or for some reason the tissues in the body cannot respond to the testosterone then the internal and external genitals will develop as a female.

The female is therefore a sort of ‘neutral’ or non- testosterone influenced genital state.

Sometimes a female baby (XX) is born with increased testosterone due to a tumour. And she has genitals that look more male than female – Congenital adrenal hyperplasia.

Other times, in a boy (XX), the tissues do not respond to testosterone and we have external genitalia that look female. And interestingly  in most – a female brain. Androgen Insensitivity Syndrome. This is what Caster probably has.

4. Brain Sex: At some time in utero, our brain is ‘sexed’ to be either male or female.  This both physiological (as in the patterns of hormone production at and after puberty) and other aspects such as identity, behaviour and orientation.

So, even at this basic foundational level of biology, many things can go wrong.

Come back next week for Gender Identity.