would there be any suspicion about the biological paternity of the forthcoming kid ?
I was a bit disappointed in Caroline's reputation.... something George was not fully apprised earlier, I gather.
Their first heterosex took place in what it was, May or June ?
and pregnancy is heard of in the end of august - having taken place some week or more to become known as far as in Naples.
Okay, three months is a time when a pregnancy is getting to show a bit.... (and women occasionally are not yet aware of their own pregnancy yet sometime in the second month.)
The kid just might be sired by George. But, if not, then it's very obvious that Caroline actually would not have been a virgin there in the Carlton House scene [oh, if she were not, then exclamation: what duplicity, what an actress].... Because, it's so unlikely that she had been porked by someone else during their engagement period, a time when she would have been watched by her parents and presumably George would have kept some company to her and additionally, they appear to have liked each other and presumably had a good enough time without outside diversions.
Btw, in those days, to many aristocratic women, a marriage was pretty much a full permission to have lovers, whichever men took their fancy. Because, the virginity was no longer at risk, and it was often thought that no one will be the wiser...
In those days, there weren't genetic tests to determine paternity. But, some things can be deduced from the outlook of the kid (bone structure, shape of skull, some other features), when the kid grows up.
All that said, it's possible that George just is glad to have a kid, not bothering to harbor any suspicions of the paternity.