Islam gives sole custody to men for children under a certain age. Isn't that sexist?
Actually there are details about Custody of a child that I learned last year.
Under the age of tamiiz (when a child understands the questions and knows how to wear his clothing, go into the bathroom and clean himself afterwared, he understands what you ask and knows how to answer then he becomes a moumayez) which is usually 7 or 8 years the Custody is given to the
MOTHER...
YES the mother raises the baby till this age. WHY? the teacher told us because she is more mercifull on her child than the father.
this is according to SHafi3i mazhab. see the book "matn ibn shoja3" in the "fasl alhadanah"
If the mother marries while the child is still not a moumayezz still under that age? The grandmother usually becomes the person to take care of him so that the child is protected.
this is not over: when the child is a that age he becomes moumayez and he becomes old enough to understand the question and respond with an answer then what?


?
Then he is asked do you want to live with your mother or father?
The child who is a moumayes decides...Usually if there are problems a trustworth Muslim judge asks him and builds using the correct rules of the only true religion, Islam.
so you see you had the wrong idea and you built something without proper knowledge.
During all this time the father is responsible for providing to the child who has not reached the age of puberty according to the rules of the religion. even if the child lives with his mother or grandmother.
If the father is dead or cannot be found the mother needs to feed the child...what can she do? But if the father is available the Muslim judge forces him to perform his religious obligation towards the child even if he is not living in his house (alnafakah)
in some countries some men try to take the child and they spread incorrect information and lie and sadly some courts do not follow the rules of the religion and they are swiming in ignorance.
let's all Please learn we all need to....
your brother Ihab