Don't know if I have understood correctly but is the mother being charged for something? And if so, is the father also being charged?
I had sex 'underage' ie at 15 and wonder if all the naysayers have forgotten what it is like to be that age. My mum allowed my bf to stay the night, but we didn't 'do it' when she was in the house at that would have felt wrong.
If my mum had tried to ban me from seeing my bf I'd have done something vastly more silly than have sex at home, I'd have run away or skived school to be with him. I may only have been 15 but I was totally in love with him. Parents forget that part - the feelings their kids have are real.
The lad in question was totally wrong for me and we split up before I went to uni, but if my mum had pressurised me to ditch him I'd have dug my heels in, and I know loads of people who ended up living with total tossers just to spite their disapproving parents. At that age you resent them telling you what to do, and the inappropriate bf just looks all the more attractive if your parents try to badmouth him.
This guy in the story was 22 which makes it all a bit unsavoury but I personally don't agree that it was child abuse or anything like that (unless the girl was coerced).
I wasn't much older then her (mere months) when I had sex and it wasn't abuse, it was a teenage fumble.