This critical research could help us to arrive at important medical advancements, especially for genetic diseases and diseases affecting cellular tissue.
If they don't grow to full term then they are not human persons anymore than an aborted embryo or aborted fetus is. If you're going to oppose this then to be consistent you have to also favor a ban on abortion.
Legality aside. From a human rights perspective, this should never be allowed. I mean experimentation is bad enough, but then we're also just going to straight up murder these scientifically created humans. I don't doubt that this could happen somewhere if it's not already happening somewhere, but if the question is should this be allowed? No. Let's leave this to sci-fi and comics. The world is a pretty disturbing place already.
How do you think we know so much about eggs and sperm. Where do you think lab rats come from? Do you think scientists are running about in the jungle stealing chimps from their homes? In the future, the issue will be super rich intergalactic criminals creating super human slave armies born with biological weapons part of them and taking over the universe. Over the top, but I would bet a coffee on it.