Julia Hislop, a licensed clinical psychologist, is the author of "Female Sex Offenders: What Therapists, Law Enforcement and Child Protective Services Need to Know" and a co-author of "Female Sexual Abusers: Three Views."

While no one who has researched sex crimes believes that females comprise more than a very small percentage of all sex criminals, a number of factors conspire to keep these women from being detected and prosecuted.

Studies consistently find that a vast majority of both male and female victims of female sex offenders tell no one. Girls face the task of convincing others that females can be abusive and that touch between females can be sexualized. Males are not socialized to report victimization. Their physiological responses can also confuse the issue of consent, leaving them puzzling to explain how, if an erection was present, there was still abuse, or how, if there was not, that sexual acts still occurred.

Female sex offenders are not easily identified. They do not tend to fit the stereotypes of male sex criminals. It is rare that they offend against strangers or stalk serial victims, for example. An exclusive sexual preference for children is also rarely seen among women.

A witch hunt for female sex offenders is unlikely to benefit society. However, it is important to recognize that they can and do commit serious crimes.

They also do not tend to conform to the titillating stereotypes portrayed in the media of attractive young teachers who’ve had sexual relations with teenagers. Females have committed sex offenses against infants, children, teenagers and adults, using varying degrees of coercion and violence. Grandmothers have committed sex offenses, as have prepubescent girls.

Laws protecting individuals from sex crimes have not historically considered female offenders. Rape, for example, often carrying more severe penalties than other forms of sexual abuse, has traditionally been defined in terms of forced vaginal intercourse. While some legal definitions have broadened, females have often been legally incapable of committing rape. Similarly, while victims of sexual violence occurring in the context of violent relationships may be protected by laws against domestic abuse, these laws have generally not pertained to lesbian couples; moreover, victims in these circumstances have historically risked their own prosecution in coming forward.

As states develop laws for determining which sex offenders are dangerous and need longer prison sentences, and which may be helped by treatment, they are limited by the lack of research concerning female sex offenders. The few studies that exist on the topic have found that overall rates of sexual offense recidivism for females are quite low. However, research to determine whether subtypes have different rates of re-offending is only in its infancy. Studies of subtypes of female sex offenders in general have produced very inconsistent findings.

Females convicted of sex offenses have little by way of research-based treatment available to them, and given the limited demand, may have none at all. Their treatment needs may be different from those of men. For example, across studies, the percentage of female sex offenders who have a history of having been sexually abused tends be about 75 percent. It tends to be severe – starting early, and/or involving multiple or closely related offenders, and/or multiple or intrusive acts. While sexual victimization does not by itself cause offending (if it did, more women than men would be offenders), it is likely to have played a role for most female sex offenders.

Given their comparatively small numbers, a witch hunt for female sex offenders is unlikely to benefit society. However, it is important that investigators recognize that females can and do commit serious sex crimes. Their victims can be seriously harmed. Continued research concerning female sex offenders is needed, and as states certify sex offender treatment providers, education related to female sex offenders should be required.