I once came across this article a few years ago and have thought about it ever since.
www.dailymail.co.uk/news/article-138109/Why-bold-women-likely-sons.html
Short put, it says that women with lots of dominant traits are far more likely to have sons (because of higher testosterone levels). Women who are more easy-going and let others say the last word are more likely to have daughters. This def applies to my paternal grandma, who was very assertive (8 sons, 4 daughters), in comparison to my maternal grandma with 5 daughters.
When I think of my colleagues, the ones with sons are far more likely to tell out loud when they are unhappy with -say- circumstances or decisions at workplace. Those who have mostly daughters tend to be much more cautious and rather accept any uncomfortable situation.
What do you think, does this sound like a plausible theory?