1. Why should I change any words? This hadith says timing is a factor. why does it say that?
2. It's not about whose chromosomes dominate whose, what matters is whether the sperm cell was X or Y. If its X that doesn't mean the female chromosomes dominate, and if its Y it doesn't mean the male chromosomes dominate.
Wife have something with it. When the Y chromosom dominate then it will become XY, resulted in that the baby gonna be a boy.
When the X chromosom (belong to the wife) dominate then it will become XX, resulted that the baby gonna be a girl.
Assalamu manit taba'al huda (May peace be upon who follow the right guidance).