It depends on what you mean by very rarely. According to the Center for Sex Offender Management, an estimated 1.6 million men and 1.5 million women are sexually abused by women when they were children.

According to Law Professor Kay Levine, it is estimated that 1.5 million girls and 1.1 million boys are victims of female sexual abuse in the United States.

The numbers vary depending on the study 600+ studies on this subject and the above information came from http://www.female-offenders.com/