I’ll give the same answer I gave to a somewhat different question several months ago:
Clone a human being, without serious physiological defects, by the year 2015. I suspect this research program would generate substantial positive spillover effects, mostly in the fields of medical technology and life extension. We might, for instance, learn how to grow organs that are already genetic matches for the recipients.When I first proposed this project, it was a reply to Alex Tabarrok’s challenge, which was (and I paraphrase), “If we absolutely must blow billions of tax dollars on something, can’t we think of something better than W’s goofy moonbase proposal?” But I actually believe my proposal is a good one, and I’d far rather see it funded privately than publicly. Indeed, given the political opposition to cloning and related endeavors like stem-cell research, private funding could be the only viable option.