Oh, jeez, that's a really scary thought. That's a *really* scary thought... of all the things that happened to Merope over the years (God bless her)... I mean, if that happened... JEEZ...
But hopefully it didn't happen. That kind of abuse would, assumedly, end up with some sort of result, right? And Morfin was the last Gaunt after Merope left - any child would have (probably) been raised by Merope, her Dad and Morfin. If you consider what you've said, Marvolo wouldn't just give the kid away...
Unless Merope was unable to bear children (which, admittedly, no one would necessarily know anyway - Marvolo and his family seem too unstable to have a physician), I think it's safe to assume that that didn't happen. I hope.
That's absolutely true, though. If they married their cousins to keep the blood-line going, Marvolo may have made Merope and Morfin... assumedly she never had kids other than Tom Riddle, so... ah, jeez. Poor Merope. Things like this shouldn't be an option, you know? It's sad that her life was so miserable that it's actually a possibility that she may have been abused like that.
She totally didn't deserve a life like the one she had, even if that abuse never actually happened. I mean...once she finally opened up to Tom Riddle Senior, he ran for the hills. How heart-breaking would that be? Rowling went all out to make us feel sorry for the poor girl...geez.
I agree. The only real problem I had with the way she handled Merope's story is that Harry seemed surprised that she would abandon her child - because I don't think any real part of her would have known, by that point, that not giving up was even an option... I mean, no one had ever done that for her, and she'd never seen it for herself... you know? Her story is so sad, but in spite of that she seemed like a good person thrown into the worst possible circumstances.