When male teachers sext or have sex with their students, nobody laughs. When female teachers do this, the titters don't stop.

Example: a wink-wink blog post on phoenixnewtimes about Gabriela Compton, a 21-year-old (former) middle-school teacher's aide in Phoenix. Compton sent a 14-year-old boy at her school a picture of herself topless. He sexted back a photo of a penis he'd found on the Internet. A few sexts later, Compton found herself accused of having sex with the boy in her van. A 13-year-old went to the police and said he'd sexted with Compton, too, and she reportedly admitted to that and the sex.

She was charged with three counts of sexual abuse, three counts of sexual abuse with a minor and one other related count. Altogether the charges carried a maximum term of 39 years in prison. In March, she pleaded guilty to the sexual abuse counts - and got lifetime probation. She'll have to register as a sex offender, but she won't go to prison.

As law professor Doug Berman says, it is not possible to imagine a male teacher getting off so lightly for having sex with a 14-year-old girl. Is Compton's light sentence typical? Can it be justified?

The answer to the first question is mostly no: Compton's wrist slap is in important ways an outlier. My Slate colleague Will Saletan has been here before me. Teacher Beth Geisel pleaded guilty to molesting a student in 2006, prompting CNN's Nancy Grace to ask: "Why is it, when a man rapes a little girl, he goes to jail, which I'm all for, by the way, but when a woman rapes a boy, she had a breakdown?"

Saletan pointed out a 1991 study that found little difference in the likelihood that male and female sex offenders would go to prison. And he updated the numbers with his own informal survey of 37 inmates who'd recently been sentenced. What was different was how long they would remain incarcerated: Saletan found that the men were in prison for an average of 11 years, while the women were there for less than two. But the women were also far less likely to have molested multiple children or to have molested kids under 16.

That is where Compton is in unusual and unfortunate territory. Since she was accused of having sex with a 14-year-old and sexting him and a 13-year-old, she's not a gal having sex with an older teen. She was doing something ickier.

Is her sentence of probation justified because women molesting boys is just different from men molesting girls? There are salient differences between men and women when it comes to sex offenses. For starters, men are far more likely to commit sexual assault than women are. They are also rearrested much more often.

The women who perpetrate this misconduct have serious problems. Like the men, they have poor coping skills and trouble showing empathy. A report by the Center for Sex Offender Management breaks female sex offenders into three types.

The first group were coerced by men into abusing children, even their own. The second were themselves victims of incest or other sexual abuse - this kind of history is far more likely for female sex offenders than for men, and the women in this category also tend to victimize young children in their own families.

The third type, labeled "teacher/lover," sounds more like Gabriela Compton. They were "often struggling with peer relationships, seemed to regress and perceive themselves as having romantic or sexually mentoring 'relationships' with underaged adolescent victims of their sexual preference, and, therefore, did not consider their acts to be criminal in nature."

The law should err on the side of caution and uniformity here. And I can't get my mind around probation for a woman who was facing nearly four decades in prison. Thirteen-year-old boys should be shielded from predatory adults the same way girls are.

Emily Bazelon writes about law and family for Slate.