Bismarck.Dracondria said:
»A kid born in space would still have the same kind of cells as normal humans and it would be very bad for them to live there for a prolonged period of time.
That idea and medical testing is based on testing "humans who grew up/lived on earth" though so theoretically it could be different for someone who wasn't.
Like blue whales for example live in a weightless environment which is why their hearts can handle pumping all those thousands of litres of blood. If they were on land they'd die very quickly due to their hearts not standing a chance against the force of gravity pulling their blood down.