Young moms, long life?: Study shows those born first to women under 25 years old tend to live longer than their siblings.

Byline: Jamie Talan

Nov. 20--Firstborn children of women younger than 25 are twice as likely to defy the average life span and go on to live beyond 100, according to a new study. Leonid A. Gavrilov and his colleagues at the University of Chicago's Center for Aging have relied on a wealth of Internet data -- from genealogy Web sites to federal death indexes -- to study centenarians to figure out why so many firstborns seem to outpace their younger siblings in the longevity race. Although there is no clear answer yet, scientists believe the phenomenon may be related to the physical youthfulness of young mothers and the eggs they produce. The study results ...