When her good friend was hospitalized, Karen Lee Carstens volunteered to help watch her 13-year-old son.
For two years, cops say, she and the boy had a sexual relationship, one where he apparently was more worried about birth control than she was.
According to court documents, at one point the boy said he had intercourse with her and, although he ejaculated on her stomach, "he cried believing he had impregnated [Carstens] but [Carstens] assured him not to worry because her menstrual cycle was due soon."
At another point, the boy thought of another way to avoid pregnancy: anal sex.
The two were upstairs in his bedroom when he was 15 while his mother was again in the hospital.
The boy "stated that he asked [Carstens] if he 'could have sex up the ass because he didn't have a condom,'" the court documents say. "Complainant stated [Carstens] refused at first citing that it would cause her pain but agreed to the request. [The boy] stated that he inserted his penis inside [her] rectum and that he 'ejaculated' inside the anus."
The boy told investigators the sex had begun around 2007, when he was 13. (Carstens is now 41.) At first it involved the boy just touching her breasts and genitals, but soon, he said in the court documents, the defendant "sucked his dick" at least four times, including once in the family's living room.
Carstens has been charged with sexual assault of a child under 17, a felony. A warrant has been issued for her arrest, but she is not in custody.