You can't blame them, especially in a culture where the male offspring carries on the family name.
I'm pretty sure these couples love their children whether they're a boy or a girl but getting help to get a boy baby out of the way to ensure lineage doesn't hurt.
It seems more important to do this if the man is the only son out of his family, if he has brothers he'd probably want at least one son too but he'd feel less obligated to provide an heir if he has brothers.
As for my family, my dad could careless, he's the only real son, as in blood relation, (his brother was adopted) from his parents and he's always complaining about how he
should've had only girls, especially on days when my brothers get into trouble.