The youngest I've ever heard of was a little girl who was raped at 5 by a male family member. She had a medical condition like precocious puberty or something. She was from a Catholic Latin American country so ... no abortion.

She barely survived. Of course, at 5, she didn't know she was pregnant or that what her male relative was doing to her was wrong.

Also, of course, after the baby was born, the church required her to ask forgiveness and perform penance for her sin.

5 years old.