He does have the same genetic parents; it’s his biological aunt, not his biological mother, who married someone different in this timeline.
I recently received your letter of acceptance to Hogwarts, addressed to Mr. H. Potter. You may not be aware that my genetic parents, James Potter#James_Potter) and Lily Potter (formerly Lily Evans) are dead. I was adopted by Lily’s sister, Petunia Evans-Verres, and her husband, Michael Verres-Evans.
He does have the same genetic parents; it’s his biological aunt, not his biological mother, who married someone different in this timeline.
I feel rather foolish now. Of course he does.
Should still be a genetic reshuffling, at least. The point of departure seems to be before his birth, so the butterfly effect would be in effect.