I think the discriminating factor here is 'consent', which was implied in the example of Turing and notably absent in cases involving children.
The 'teenage boy' (which implies anybody between the age of 10 and 19 inclusive) was in fact 19, Turing himself was if I get it all right 42 at the time.
> (which implies anybody between the age of 10 and 19 inclusive)
So ? That's what I wrote wasn't it ? I realize 19 is 'a teen' but it is at the end of the spectrum. Saying just 'teenage' makes it ambiguous and is suggestive of someone much younger than nineteen, you tend to guess that must be in the middle of the range, whereas in fact it was the last entry in the range.
The 'teenage boy' (which implies anybody between the age of 10 and 19 inclusive) was in fact 19, Turing himself was if I get it all right 42 at the time.