It’s the dads who choose what sex the child will be! Did you know that?
They can’t consciously choose it though, it just ‘happens’. Chromosomes determine it!
But chromosomes can go wrong too. Chromosomal abnormalities can prevent conception, cause miscarriages, or if pregnancy goes to term it can cause developmental issues in the child – which can range from imperceptible to significant.
But what are chromosomal abnormalities? Too complicated to describe here, that’s for sure!
Genes are COMPLICATED – even describing them in the most general of terms is complicated.
Here’s a short primer!
We are supposed to have 46 chromosomes in each of our cells. The sperm (which is a single cell) gives 23 of dad’s chromosomes, and the egg (which is also a cell) gives 23 of moms. Bingo, the first cell is created at conception and has 46 chromosomes, which are joined together as 23 pairs!
As the embryo develops into a child every new cell that is created will have the same 46 chromosomes – numbered in pairs, uninspiringly from 1 to 23.
Number 23 is the odd one out, this is the one that determines our sex, and it is the sperm that decides it. All moms’ eggs have X chromosomes, but only half the sperm have an X chromosome, the other half have a Y.
Actually, it’s not true to say “half the sperm” have the X and the other half have a Y – the ratio is determined by hormone balance in the man on an ongoing basis.
If the sperm that fertilises the egg has an X chromosome the offspring will have an X from mom and an X from dad, so they will be XX – which if female! If the winning sperm has a Y chromosome, then the offspring will have an X from mom and a Y from dad so it will be an ‘XY’ – therefore a male!
(I guess the ‘multiple genders’ argument is a social one rather than a physical one!)
But what about abnormalities?
Chromosomal abnormalities are detected by looking at the 23 pairs to see if any are missing or if there are any extra.
Why would there be any missing, or an extra one?
Two reasons: Something went wrong in the egg or sperm before they met – OR - something went wrong after conception.
If something goes wrong in the egg or sperm before conception then either no conception happens, of if it does then every new cell will carry the same error, usually, but not always, resulting in a miscarriage.
If the mutation occurs AFTER conception then only the affected cells, and their ‘daughter cells’ which arise from them, will be affected and it is most likely that the rest will not be affected. This is called Mosaicism.
If a child survives gestation and is born with any one of these chromosomal ‘abnormalities’, they will have some kind of compromised function throughout their life. The severity of it can range from insignificant to very serious.
For example, if genetic testing reveals that the child has an error or mutation on chromosome number 21 such that they have 3 instead of 2 chromosomes at that location on the gene, the child will be diagnosed with Downs Syndrome.
Remember that girls have XX chromosomes at number 23, and boys have XY. Well if a boy, who is XY, has an extra X at that chromosome (XXY), or indeed an extra 2 (XXXY) or even 3 X’s (XXXXY) (which can happen but is rare) then they will be diagnosed with Klinefelter’s syndrome! A good friend of mine has this!
Another less known syndrome is Turners Syndrome, where girls have a missing or partially missing X chromosome at number 23. Remember if you have XX at number 23 you are female. In Turners Syndrome you are missing (or have a partially missing) X, and yet you are still female. (I did say genes were complicated!)
What causes these ‘errors’ in chromosomes?
I’m not going to say I know all the answers here, but I can give you a very useful albeit general answer that you can do something about. Be as healthy as you can before you conceive a child!
They are not ‘hereditary’. They arise randomly.
The body has mechanisms for repairing damaged genes – and to completely oversimplify things - one nutrient – Folate – is intimately involved in repairing damaged DNA. So a deficiency of folate can put not only yourself at risk of cellular damage, but it can also affect your offspring. Future dads and moms need to have enough nutrients in their system at all times to repair damaged DNA.
A whole soup of nutrients is needed to repair damaged DNA, and a whole raft of reasons explain why it gets damaged in the first place. Oxidative stress is the principle one, but imbalanced hormones, over or under active immune systems, psychological stress, traumas – all kinds of things conspire together to break the system and take fertility offline. Any wonder it takes a lot of work to fix it once it’s broken!