There are 351 men in California locked up in a state mental hospital as sexually violent predators, prone to attack again and again.
Then there is Charlotte Mae Thrailkill.
The 43-year-old mother of two is California's only female violent sex offender, confined to a maximum-security state mental hospital after experts decided she was too dangerous for release.
Only a handful of women, including Thrailkill, have ever been confined to mental institutions under state laws that allow for civil commitments of sex criminals after they have served their prison terms.
Women are less likely than men to commit sex offenses, but they also are less likely to be reported and prosecuted. Many experts contend that women commit sex offenses far more often than is generally believed.
"It happens a lot more than gets reported, and I think part of that is due to our culture," said Steven B. Blum, a consulting psychologist to a sex offender program in Nebraska. "There are a lot of women who have sexual contact with teenage boys, and they don't get reported."
In the state's regular prison system, only 103 of the 9,746 women behind bars--1.06%--are there for sex offenses, including statutory rape and lewd acts with children. That compares with about 12,500 men, 8% of the total male prison population.
Paul Federoff, a forensic psychiatrist in Ottawa, Canada, said one of the female sex offenders he counsels is an exhibitionist. She opens her living room curtains and strips off her clothes when people pass by.
He told her that unless she stopped this illegal activity, she would be arrested.
" 'Doctor, if someone calls up and says he saw me disrobing in the window, who do you think they are going arrest? Me or him?' " Federoff said she replied.
"And she is absolutely right."
It was widely assumed until recently that women just didn't sexually abuse children, Federoff said.
But during the past two decades, as parents and others have encouraged children to disclose improper sexual behavior, kids have been confiding about abuse by women as well as men.
"Now we are discovering that there are a lot of women who do sexually abuse children, but they get away with it," Federoff said. "There is a growth industry of treatment programs, particularly for adolescent female sex offenders who commit a lot of the crimes while they are baby-sitting."
Thrailkill, whose sexual predator status is up for review by the state in September, told psychiatrists she molested children, ages 5 to 8, whom she baby-sat or enticed into her Santa Rosa apartment to play with her children. Her story, pieced together from court records, is a less a rarity than crime statistics suggest.
Thrailkill, the third of six children, was born with scoliosis and a deformity in her mouth that caused speech difficulties. "She stated that school was difficult for her, not only due to her learning difficulties but also due to constant ridicule by her peers because of her physical deformities," according to a state mental heath report on file in Santa Rosa.
When older children picked on her during elementary school, "she would then bully and beat smaller, defenseless children," according to the May 2000 report.
She told counselors that she had a good relationship with her father, but complained that her mother regularly beat her with narrow leather straps, sticks and her fists. Thrailkill ran away several times between the ages of 11 and 16 and was gang-raped at age 15, she told authorities, by four men who grabbed her off a street.
That same year she was severely wounded in a random shooting and spent nine months in a hospital. She never returned to school.
Thrailkill married a U.S. Marine at 19. They had two daughters. She left him five years later, complaining their marriage was sexless, and won custody of their daughters.
Women who commit sex offenses often fit into one of three categories.
The "teacher-lover" or "Mrs. Robinson" type has sex with underage boys. These women fancy themselves in love with the boy and don't see the relationships as harmful, experts say.
The women tend to be immature and get an "ego boost" from the involvement, said Blum, the Nebraska psychologist, who counsels such offenders. "Without exception, all of our patients have had a substance abuse problem and also were partying with their victims," he said.
"Generally the male doesn't feel victimized," he said. "A lot of teenage boys would see that as their lucky day."
Despite such perceptions, researchers maintain that many boys may be left confused and angry, and if they are particularly young, they may be sexualized too early and have sexual problems later in life.
Women who have sex with minors make the same kinds of excuses as their male counterparts, said Florence Wolfe, co-director of Northwest Treatment Associates, a Seattle-based program for sex offenders.
Wolfe said the women tell her: " 'I wanted the closeness, the excitement, not the sex. I wanted the safety. He was 13. I was only 27. The kid wanted it.' "
A study of college students and prisoners found that 16% of the college men and 46% of the male prisoners reported they had sexual experience before the age of 16 with a woman at least five years older. The average age of the men at the time of the contact was 12.
A second type of offender is called "predisposed" and includes mothers who molest their children.
Wolfe says more than 50% of the 150 female offenders she has counseled molested their own children, primarily daughters.
Some women considered predisposed to sexually molest children are pedophiles with an assortment of mental illnesses. Wolfe described one such offender she has met as a sexual sadist.
"She looks like everybody's lovable grandmother: pink cheeks, gray hair, chunky," Wolfe said. "She volunteered to baby-sit for young single moms. They jumped at the chance."
Most of this offender's victims were girls, and most were not yet verbal. The woman would slap them until their teeth cut their mouths or start a nosebleed. Their pain gave her sexual pleasure, Wolfe said.
"She finally molested a 4-year-old, and that kid was verbal enough to tell someone," Wolfe said.
The third type of female sex criminal is called the "male-coerced" or "male-accompanied" offender. These women commit sex crimes in the company of a man. Thrailkill, who declined to be interviewed for this story, fits in this category.
Thrailkill told psychologists that she had sex with 20 to 50 different men in the year after her divorce. She eventually met Daryl Ball and allowed him and his young sons to move into her apartment in Santa Rosa. Ball introduced Thrailkill to sex with children, according to a state Mental Health Department report filed with Santa Rosa Superior Court.
Thrailkill at the time was thin, with long, dark blond hair. She looked older than her 27 years. She was quiet, shy and submissive, attorneys recall.
Seven years her senior, Ball was a brutal boyfriend, Thrailkill told others. She said he violently sodomized her, threw her from a car once and beat her to unconsciousness twice.
She molested his sons, police said. Not only was Ball aware of the molestations, he joined her in having sex with children, police and criminal records say.
Ball and Thrailkill had sex a couple of times a day with children and with as many as five children at a time, she told psychiatrists. The victims were her boyfriend's sons and other children in the apartment complex whom Thrailkill baby-sat or lured into their apartment.
During the eight months in which she molested, Thrailkill drank and used methamphetamine, first snorting the drug and later injecting it, she told mental health workers.
"When she was intoxicated, she was sexually promiscuous, violent and sexually perverse," according to a May 2001 report by the state Department of Mental Health.
Both Thrailkill and Ball threatened the children that their parents or siblings would be killed if they told anyone. Eventually, one of the children did tell, and Thrailkill and Ball were arrested.
When a parent of one of the victims confronted Thrailkill, she said she molested because she was "afraid" of Ball, who was then 34.
"He made me do it," she said.
But in records on file at the Santa Rosa courthouse, Thrailkill admitted she molested five children--four boys and one girl--on her own. She said she abused them to get even with the victims' parents.
Thrailkill typically endured extensive mistreatment in relationships, a mental health evaluation found. When she finally felt sufficiently hurt by the abuse, she lashed out at others.
"She admits she takes anger out on weaker, often innocent individuals," a mental health counselor wrote.
A 1981 national study of both reported and unreported child abuse indicated that as many as 24% of boys and 14% of girls who are molested are victimized by women.
Although sexual abuse by both men and women is underreported, female offenders are less likely than men to be prosecuted.
"I have had so many clients, both males and females, who talked about mothers or their baby-sitters molesting them," said Charlene Steen, a psychologist in Napa who has treated sex offenders for 20 years. "And they were never reported."
Dr. Robert Kolodny, who has directed behavioral research institutes and written about sexual behavior, said he periodically gets calls from befuddled prosecutors who have cases in which a man has accused a woman of rape.
"Although it sounds counterintuitive, men can indeed be raped," Kolodny said.
People commonly assume that men cannot be forced into sex against their will. But experts say men may be physically capable of sex even while under extreme duress.
Female rapists are sometimes acquaintances of their victims and get them drunk or drugged before they force them to submit to sexual acts.
"We don't really have good studies that would give us an accurate picture of how often it happens, but it is not rare ... not a one-in-a-thousand kind of thing," Kolodny said.
Some case studies describe rapes of men committed by two or more women. In a report in the Archives of Sexual Behavior, two physicians described 11 cases of rapes of men, including a man who picked up a woman in a bar and then went to a motel with her.
The man had a drink and fell asleep, the 1982 report said. When he awoke, he was gagged, blindfolded and tied to the bed. He heard the voices of several women.
Steen, who is also a lawyer, described one man who was drugged and raped by two women and a man. The victim was later found wandering the streets with his clothes tied around his neck.
Observed Steen: "There are women out there who are doing some pretty horrible things."
Thrailkill initially faced more than 50 counts of felony child molesting. She pleaded no contest in 1988 to five counts of molestation in exchange for a 14-year prison sentence.
Ball, whom Thrailkill married after the arrests but divorced while in prison, pleaded no contest to several counts of lewd and lascivious conduct upon children and was sentenced to 24 years in prison.
Thrailkill began serving her sentence in September 1988 and was paroled in September 1994. She then worked in construction and had what court records described as two "normal" relationships with adult men.
In July 1996, she violated her parole by using alcohol, associating with convicted sex offenders and having contact with children.
She returned to prison and again was paroled in March 1998. Within a month, parole was revoked because she had used alcohol. The state began proceedings to commit her as a sex predator, and she did not oppose the effort.
Marie Case, a Santa Rosa criminal defense lawyer who represented her, said Thrailkill was "intimidated by the whole proceeding" and horrified that media coverage might hurt her daughters, who were then in school.
"I found her to be very shy and very private, and it was very painful for her to discuss" her past, Case said.
Thrailkill was certified as a sexually violent predator in September 1998 and sent to Patton State Hospital in San Bernardino County.
Like other sex predators who have been committed, Thrailkill's status must be reviewed by the state every two years. She may be recommitted only if two mental health experts determine her mental problems make her likely to molest again.
During therapy, she has expressed regret about her two daughters, who are now adults. Thrailkill conceded at the hospital that her daughters had been "sexual victims of her husband and emotional victims of her," a report said.
Ball, now 50, was released on parole in January. Two state-appointed mental health experts evaluated him and found he does not have a mental disorder that makes him likely to molest again.
Thrailkill is scheduled to leave Patton in September unless the state tries to renew her commitment.
A staff psychologist with the department wrote that Thrailkill does not wish to be released until she is convinced she can "manage" her behavior. According to a May 2000 report, she has "genuine shame for her behavior and remorse for her victims."
"She has never shown any interest in coming out," Case said. "I think she feels safe there."