https://en.wikipedia.org/wiki/Infanticide

"In many past societies, certain forms of infanticide were considered permissible. In some countries, female infanticide is more common than the killing of male offspring, due to sex-selective infanticide.[3] In China for example, the gender gap between males and females aged 0–19 year old was estimated to be 25 million in 2010 by the United Nations Population Fund."

Also:

"The historical Greeks considered the practice of adult and child sacrifice barbarous,[30] however, the exposure of newborns was widely practiced in ancient Greece, it was even advocated by Aristotle in the case of congenital deformity "

In her Nobel winning novel, The Good Earth, Pearl Buck recounts how the family, during a famine, allows the daughter to starve to death, but then at the last moment the father changes his mind and gives her some food. The child grows up brain damaged, having been deprived of food for several days, when she was only 1 or 2 years old. This part of the novel (like everything else in the novel) has been praised for its realism.

Around the year 610, early in his preaching, one of Muhammad's first revelations from Allah is that parents should no longer leave their newborn daughters to die in the desert. He would not have felt the need to make this pronouncement unless it was a common practice. And remember that his own sister had been set out in the desert and allowed to die as soon as she was born.