This topic has been debated ad nauseum on other threads.
The circumstances are a reflection of human anatomy & reproduction.
Men have control of ejaculation. They do not have control after they've ejaculated their baby batter up a woman's vagina.
Condoms may fail, though rarely if used correctly.
All forms of contraception may fail.
If your son does not understand these facts, then he is not mature or responsible enough to be having sex.
And on the flip side ...imagine an abortion being coerced on a woman who's fallen pregnant by accident , who has decided she doesn't want one. That's the flip side of your "imagine it was your son, with no choice in having a child".