Second of first son. my older brother has four kids, all girls, and they are out of the procreation game. I have two, also both girls. My Lebanese father in law half-jokingly scorns us with the Abu Banaat title, which is an Arab insult meaning "father of daughters."
Notably, my father was an only son and while his father had two brothers, one hung himself in the barn when he was a teenager and the other wasn't right in the head and died childless.
Long story short, if I don't crank out a son, the entire line dating back to the founding of the current "estate" dies with me.