Newt and Tina are walking around Surrey, a No-Majs neighborhood; when they hear a crack the tell tell sign of Apparition and a roar of a motorcycle. Before Newt or Tina could react, they heard a woman crying.
Tina and Newt give each other a look before running towards the crying sound, the scene they came across surprised Newt.
Transfiguration Mistress Minvera McGonagall aka Hogwarts Old Battle Axe was crying in front of a Muggle house because of the babe that's in on the front step; she can't do anything without Albus knowing.
'How I wish one of my former students any of them would walk past right now.' McGonagall thought to herself not knowing that her wish was going to become true.
"Prof. McGonagall, is everything alright?" asked Newt worrily because seeing one of his toughest teachers crying.
When McGonagall turn around her eyes went wide to see Newt Scamander and his wife in front of her. Tina asked the older witch if that is a baby on the step, and after a nod she picked it up.
Tina move the blanket away from the baby face to see a boy looking at her with instenes green eyes that she has ever seen on one other person before: Lily Potter.
Newt asked about the Potter's and when they found out that Voldemort killed them and tried to kill Harry, Newt looked over to his wife and saw a look he knew very well.
After a quick debate, hugs from McGonagall, and pretty quick cuts from the Goblins; Harry James Potter is now Harry James Scamander the son of Newt and Tina. Tina owled both Amelia Bones and William Greengrass to be Harry's new Godparents, they replied yes a couple of days later.
Instead of growing up hated and being abused; Harry grew up with his dad's animals, his Uncle Jacob and Auntie Queenie, His three best friends Neville Longbottom, Susan Bones, and Daphne Greengrass. When Harry is about 5 he meets a wonderful girl named Luna Lovegood and their magics mix, so their families wrote a betrothal contract for the two.