What's fine for one sort of recipient to know about you may not be acceptable for another.

WSJ: The End of the Email Era

This form of gift can be more meaningful if you take the time to find a charity that the recipient likes to support.

FORBES: 6 Holiday Gifts That Make Financial Sense

You would think that a chimeric immune system would be more active, not less, and would therefore attack the recipient's other organs, since they look foreign to the transplanted immune cells.

ECONOMIST: Organ transplants