Experts said when it comes to teachers and students, there is no such thing as consensual sex.  It's a violation of trust and professional boundaries, Charol Shakeshaft, a former Hofstra University professor said of the March 20 encounter Nassau police say happened between Heather Kennedy, 25, a math teacher at Wantagh High School, and a 16 year old boy who is a student at the school.  Kennedy was arraigned yesterday on charges of statutory rape and endangering the welfare of a child.  The age of sexual consent in New York State is 17.  I believe that females get a lot more attention [in the media] because I think it adds another dimension, Shakeshaft said.  People don't seem to think it's child abuse then.  We've been very slow to accept the fact that boys and girls are abused by both men and women, Mike Lew, a Brookline, Mass., psychotherapist, said in an interview after the February 25 arrest of Maria Commins, a Greenport teacher's aide who was charged with raping her son's 15 year old friend.  Female offenders often target younger men for a sense of power, said psychologist Mic Hunter, author of Abused Boys: the Neglected Victims of Sexual Abuse.  But some offenders don't admit their actions were abusive: Commins told police that she and her victim were in love, and Seattle teacher Mary Kay LeTourneau, 43, married her former sixth-grade pupil after she served 7 1/2 years in prison on charges that she had raped him.  They believe they're victims or they're equals, said Hollida Wakefield, a psychologist in Northfield, Minn., who has treated sex offenders and victims.  It's hard for them to comprehend that it's criminal.