I read a book a couple of years ago and now I can't remember for the life of me what it was called or who it was by. I was going through a fluffy romance phase and bought a load of chick lit on my Kindle including some by authors I had never read before.
Anyway, this particular book, if I remember correctly, centred around a family where a dad in his 50s or 60s with adult children was engaged to a beautiful woman the same age as his kids. The woman is obviously very young and beautiful but quite distant, and it is implied that she had a deep, dark, secret. At some point we are privy to an exchange between her and her brother during which we learn that she is estranged from their parents. The adult son of the father is struggling with his conflicting feelings towards his future stepmother. On the one hand he mistrusts her, thinks she's only after his father's money, knows she has some sort of terrible secret, and is trying to find out what it is. On the other hand, the more he tries to find out what her secret is, the more he starts to realise he is attracted to/in love with her himself.
At the very end of the book the young woman ends up breaking up with the father and getting together with the son, and we learn - literally in the last chapter - that her deep, dark secret is that she is actually a trans woman. As far as I can remember, the book ends with them about to have sex and the trans woman telling her ex future stepson and new boyfriend that he won't even notice that her vagina isn't a natural one, and that if anything it's better than the real thing.
If it had been a paperback book I would have put it on the compost heap in disgust, but as it was a Kindle book I think I must have settled for permanently deleting it from my purchased books, which is why I can't find it or tell you what it was.
In all fairness, the book was a bit crap even before I got to the end but I was ploughing through because I don't like to leave books unfinished, only for the moral of the story to be that we can't tell whether someone is male or female and that a mangina is better than the real thing.