I'm pretty uncomfortable with the entire idea of sperm donations, actually. Voted no.
Interesting, I don't think I've heard an argument against them before. Why?
Really? It's the same arguments that are used against IVF in general, which are pretty common.
1) Why go to so much trouble to create a new life when there are already so many orphans in the world? It's basically just because people are vain, they can only love a child if it has their genes. Such people shouldn't be parents in the first place.
2) It destroys a crap ton of embryos (bad if you're pro-life).
3) It often leads to unwanted multiple births. Again, same issues as number 1, waste of resources. Additionally, when people unexpectedly have 5 kids they almost always have to go on public assistance. So tax payers end up paying to support people who just blew 100k on making 5 test tube babies, 4 of whom they didn't even want.
4) It often leads to premature birth. Again, waste of resources. Why are we creating sickly babies when there are plenty of healthy ones already?