Sex between an adult and child is a crime in every state, whether the older partner is male or female.  It is believed by most experts that affairs between grown women are likely to be treated more gently by the legal system.  The case of Mary Kay Letourneau, the elementary school teacher who began an affair with a former student when he was 13 seems to bear this out.  After she pleaded guilty to child rape, a sympathetic judge suspended all but 80 days of a 7 1/2 year sentence, and returned her to prison only when she violated a court order by continuing to see her teenage lover.  Letourneau was already over 30, married and a mother when she began the affair, which resulted in two children.  Cases of older women and teenagers invite more snickering than serious legal discourse about improving the system to identify these crimes.  People don't look at the (male) kid as a victim.  They look at him as being lucky, said Howard Davidson, director of the American Bar Association's center of Children and the Law.  Sexual assaults are much less likely to be reported when the victims are teenage boys, according to Kenneth V. Lanning, superisory special agent at the FBI Academy at Quantico, Va.