illicit affairs

Title:  Can a Muslim man marry a Muslim woman who had a child through illicit affairs?A Muslim woman had a child when she was 15.  She married the child's father 6 months into her pregnancy.  The child was born into the world after the Muslim girl and the child's father were married.  14 yrs later, the Muslim girl and the father of the child got a divorce.  What are the rules in islam about a Muslim man marrying a Muslim woman who became pregnant prior to marriage?  Local social customs say that marrying such a woman will bring trouble for the family for 7 generations.  Is this social custom at all islamic?