The older Chinese tended to nickname their children after animals and give their boys, a girl’s name or a girl a boy’s name.
My informant knew about this custom because his older sister was given a boy’s name to ensure that the next child would be a son. His sister was born in the 1940s, and he learned about it in the 1950s when he was very young.
There are many reasons for this. In the past, people used to name their children after animals to avoid the demons from taking their children away because they would get confused when the parents would call them animals in hopes that the spirits would take the animals instead. Another reason is that the spirits would think that there was something wrong with the children if they’re called names for the other gender. Often though, Chinese families would call their older girls (especially families with no boys) by boy names in the hopes the next child would be a boy.
This is because, boys are very important for more traditional Chinese families. In the past, the daughters would become part of the family they marry, but the son would remain, carry on the family name and take charge of the farm and parents.