The courts aren't biased against men. Equality is treating people in the same position in the same way.
The majority of men (90%) in employment with dependent children work in full time inflexible jobs whereas the majority of women with dependent children don't work or work part time to fit around commitments to children. See;
http://www.dad.info/w...k-and-kids-in-the-uk/
When parents separate the law says that generally not disrupting a child's sense of security and established bonds is in the child's best interests. That means that fathers are disadvantaged and usually a child will live with the mother for the majority of the time.
However, fathers are treated in the same way and when they look after the children most of the time before the parents' relationship breakdown there is every probability they will continue to look after the children most of the time after separation and the mother is disadvantaged.