Depends on what the scientists are doing… If they’re trying to create a new human life, that is wrong. If it’s with animals, it isn’t really any different (morally speaking) from other forms of animal husbandry.
Also, if they’re making a replacement part of a human out of their own or a willing donor’s tissue, such as helping them grow a new nose as the above poster mentioned, that is medicine. Practicing medicine is not a sin.
Some people do find the idea creepy, but creepiness does not make things sinful. Some people are sickened by the sight of blood- that doesn’t mean helping injured people with transfusions is sinful!