Love, as applied to children, does not transcend dna.

Probably most people who are adopted are adopted by relatives (often informally, and this doesn't always show up).

A mother is naturally closer to her own children than someone else's. Ditto for a father.

I've known cases where people could not have biological children. The couple adopted kids. The father got a girlfriend and knocked her up. He then started paying all this attention to the mother of his biological child, and not so much to his adopted kids.

My friend told me of a case where a couple adopted kids.
Then they found out they could have kids. They loved their biological children a lot more than they did their adopted daughter.

And as someone who has had to deal with stepparents, while my stepfather is okay, he is a lot closer to his biological children than he is to me.

My father had a common law wife situation. I was never really close to her (my stepmother of sorts) at all!

When it comes to children, dna matters!