I dunno how many cultures put an emphasis on it like the Chinese or Japanese, but not having at least one boy to "carry on the family name" is... a big thing.
In fact, when there was a limitation on how many children could be had (or even if they couldn't take care of more than a couple kids), there was a thing decades ago where baby girls would be left abandoned in public transport lockers to just... die.
Every culture has an ugly side in one way or another. It's sad but true.