There have been 2 zoos in Germany where young gorilla females had trouble raising their infants in the last years - Heidelberg and Münster (and Berlin, but that is a different story). And in both zoos, the zoos took the female babys away and rescued them, while the males were left with their mothers and did not survive.
Heidelberg - male gorilla born to very young Chuba in 2002. She did not take proper care of him, but he was left with his mother. When he was injured he was taken away, the vet attended him and then he was given straight back to his mom. He died being 3 months old. Chuba`s next baby was a female, Kissa, born 2004, and Chuba took better care of her then she did the first time. However, when Kissa got sick, she was taken away from her mother and she is now raised in the gorilla kindergarten in Stuttgart. Chuba is since then on the pill to learn mothering behavoir from the female of teh group who is raising her baby before getting pregnant again.
When the second young female of the group, Doba, gave birth in 2007, she lacked milk (I think) and the - female - baby was removed for handraising. She has been named Kiki and she stayed in Heidelberg, in the hope to integrate her into the gorilla family. She is having contact with the other gorillas over the fence since many months.
In Münster - the first gorilla infant born there was a female (Mary), and her inexperienced mother wasn`t looking after her that well. She was left with her mother but died about 4,5 months old. The second baby, born by the other young female, also a female (named Mary II) was removed after a few weeks and is now looked after in the Stuttgart Kindergarten. The third and fourth infants (one born to each young female) were both males and they were left with their mothers... one just died, the other one seems to be doing well.
It seems that male and female infants with not-so-skilled mothers are indeed treated differently. Not that I am condemming that; it is very necessary that young females get the possibility to make mistakes and learn from then even if this means the death of a gorilla baby.