YA book- strict religious family keeps "monster" hidden in basement

[Hannah]

YA book- strict religious family keeps "monster" hidden in basement (is really a bastard child). I think the main character's name is Mary. She eventually gets the courage to run away with the "monster" and they go live wth her sister.

[Kelly]

Could it be The 3NBs of Julian Drew by James Deem?

(Probably not, but I thought it might be worth looking at, if only because your book could be on a booklist with this one somewhere.)

[Kris]

3 NBs of Julian Drew by James M. Deem - Kelly's suggestion

[Juels]

Sounds like Abomination. I'm using the app. So I can't provide the link right now. If someone else could post the link, that would be grand. Otherwise, I'll log in later to update it.

[Kris]

Abomination by Robert Swindells - I think this is Juels' suggestion

[Juels]

Yes, that's the one I was thinking of. Thank you Kris.

[Lobstergirl, au gratin]

Hannah, was your book "Abomination" or are you still looking?