when it's born she hands the child to its father for him to raise with his partner who adopts the baby. In that relationship there is a father, a mother and a birth mother. What is your problem with that?
You mentioned 'partners' not women.
But I have a huge problem with an immediately post partum mother 'handing' away the child she has just given birth to. English law does too, for now at least, as I've said repeatedly.
Do you seriously not see any issues at all with taking a tiny newborn away from the woman who has just birthed it?
I can see the difference but I can also see similarities
What similarities? Surrogacy involves the 'commissioning' of a baby with the intent of taking it away from its mother as soon after birth as is possible/legal. That's true even if the surrogacy is 'altruistic'. Your scenario involves a family making the best of a bad situation where a young girl has accidentally become pregnant. The mother will continue to play an active role in her child's life even if she is not 'officially' the mother.
So really it's a dumb comparison.