What do you mean, girls have more lives?

It means having fewer sons and more daughters.

This is a superstitious statement and can't be believed. The chances of having a girl and a boy are all 50%.

Daughter refers to the female children born by both men and women. It can be divided into biological daughters (daughters born to both husband and wife), stepdaughters (daughters born to spouses and ex-husbands, ex-wives or others) and adopted daughters (adopted daughters). The word "daughter" is a polite address for someone else's daughter.