We're Already Designing Babies  Even today, parents are
selecting for the traits they want in their offspring. But how
far should the genetic tailoring go? John Javellana/Reuters
ASPEN, Colo.—A new type of in-vitro fertilization procedure
allows doctors to transfer the mitochondrial DNA from one woman
into the egg of another, effectively creating a baby with three
parents: The father, the egg mom, and the mitochondrial mom. The
method is intended for a tiny fraction of women who have what's
known as a "mitochondrial disease," which increases the
likelihood of bearing children with severe birth defects.  Both
the U.K. and U.S. are currently debating permitting clinical
trials for the technique. As the New York Times described in a
recent story:  In Britain, national law prohibits altering the
germ line, but Parliament is very likely to vote later this year
on whether to allow mitochondrial replacement to move forward.
Likewise, this February, the F.D.A. held a meeting to examine
the possibility of allowing cl