Because families were only allowed one child and they wanted their family names and legacy to live on, tens of thousands of Chinese girls were sent out for adoption to other countries or just aborted, until they had a male heir. Their male-to-female ratio is so skewed that it's physically impossible for all their men to get (exclusive) wives, so even bottom-of-the-barrel women are desirable, due to scarcity.
To add to this, it wasn't simply out of some abstract "legacy". China was poor as fuck back then, and sons were the parents' retirement. Single women were/are useless, and married women would be too busy taking care of her husband's family/children. Her own parents would be screwed if they only had a daughter.
Because families were only allowed one child and they wanted their family names and legacy to live on, tens of thousands of Chinese girls were sent out for adoption to other countries or just aborted, until they had a male heir. Their male-to-female ratio is so skewed that it's physically impossible for all their men to get (exclusive) wives, so even bottom-of-the-barrel women are desirable, due to scarcity.
To add to this, it wasn't simply out of some abstract "legacy". China was poor as fuck back then, and sons were the parents' retirement. Single women were/are useless, and married women would be too busy taking care of her husband's family/children. Her own parents would be screwed if they only had a daughter.