I saw a spate of headlines over the weekend that proclaimed something like, “Now scientists create a sheep that’s 15% human.”

15% human? Really? Isn’t that like being “a little pregnant”?

Followers of this blog may already know that I’ve written a fair bit, most of it disapproving (at least with respect to the newest genetic innovations), on the creation of chimeras. One of the concerns raised about this latest effort is the potentially devastating effects of so-called “silent” viruses, which are harmless to animals but could migrate with the harvested parts.

According to reports, Dr Patrick Dixon, an international lecturer on biological trends, warned: “Many silent viruses could create a biological nightmare in humans. Mutant animal viruses are a real threat, as we have seen with HIV.”

I’m inclined to think that this kind of work respects neither the animal nor the human person. And the latter is in part illustrated by the fact that if you just went off of what the headlines said, you’d think it’s possible for something to be partially human. It’s really a confusion about what it means to be human. You either are or you aren’t.