Three cheers to Paul. He is correct that many scientists insist that if we expended the same amount of time and money on alternative research methods, we would get better results.

In fact, in a USDA press release January 12, 2006, Health & Human Services
Secretary Mike Leavitt said:

"Currently, nine out of ten experimental drugs fail in clinical studies because we cannot accurately predict how they will behave in people based on laboratory and animal studies."

More importantly, you do not settle whether experimentation is justified by merely showing that it is of some value to humans.