Research into human-animal chimeras could have a therapeutic payoff, but the work brings up thorny ethical questions.

For decades, the idea of growing human tissue inside another species sounded like something that belonged in a science fiction movie. Today, laboratories are exploring a far more practical version of ...

Imagine having the strength of a wolf, the balance of a cat, or the ability to fly like a bird. For centuries, these ideas have belonged to mythology and science fiction. Today, advances in genetics ...