So I've been learning about many genetic conditions at school, one of them being achondroplasia, the most common genetic disorder that causes dwarfism. Tyrion Lannister (and his actor, Peter Dinklage) has achondroplasia. Women who are pregnant with a baby suffering from this genetic condition often need C-sections to deliver safely, which is why Tyrion's mother died during childbirth (since there are dragons in that fictional universe, but not the practice of modern medicine).
Here is the part I find most interesting though: Achondroplasia is most commonly caused by a 'de novo', i.e. spontaneous, mutation that happens in the gamete, almost always the sperm (not the egg), and the frequency of this mutation positively correlates with the age of the dad. The older the dad is, the more likely his sperm will have the mutation causing achondroplasia, and his child will be born with the condition.
I find it interesting that Tywin Lannister is always treating Tyrion like a piece of shit because of his dwarfism and the fact that he thinks his son was the cause of his beloved wife's death. I don't think that it is fair to think of genetic mutations and disorders as faults of any parents, but if Tywin is going to blame anyone for his wife's death, it should be himself, since that mutation (with like 99.99% certainty) came from him.
Tldr; Tywin is an asshole and he's basically an equivalent of Henry the Eighth, blaming his wives for absence of sons when he was the only one responsible for sex determination.
