Here is a hitherto unsupported foundation for his argument. To date, we have found that we can take adult stem cells and do the things we want to with them. We have not found actual limits. In the case of embryonic stem cells, so far we can't even make them take the first steps. Quite aside from the ethical issues - which are quite important - embryonic stem cell research in more than a very basic fundemental level appears to simply be dumping money down a hole.
Michael Reagan talked about this before the election. he confirmed that embryonic stem cell research was not producing good results. In fact, the research was going badly. For this reason there are little to no private donations or funding for it. This is why the push is on for gov. funding.