What is the ruling on Muslims cutting the hair of their heads, and is it a condition that the hair be cut to the same length from all parts of the head?

Trimming hair and taking from it evenly is permissible, provided it does not involve imitating disbelievers. As for cutting some of it and leaving some (Al-Qaza'), it is not allowed and is prohibited. This ruling applies generally to both men and women. Hair cutting must also be free from men imitating women and women imitating men.