Child Custody in Cases of Divorce

My friend Rohan and I had a heated debate yesterday over this one. Question is: if a couple gets divorced, and the child was born out of wedlock, does the mother hold a higher custody rights?

Rohan says, "No, under Section 6 of the Hindu Minority and Guardianship Act, 1956, if the mother is not married to the father, the mother still gets preference in custody due to her natural guardianship." I disagree, "But think about it, bhai! The mother may not be married, but she might still be the one taking care of the child. Why should her marital status decide custody?" Now, I need help from you guys. What's the rule of thumb here?