Birthdate: May 27, 1969 for BOTH
Bagwell obviously had to retire early due to his shoulder problems, but Frank Thomas is still playing and has shown he isn't done.
Stats:
Jeff Bagwell
http://www.baseball-reference.com/b/bagweje01.shtml
Frank Thomas
http://www.baseball-reference.com/t/thomafr04.shtml
Both were MVPs of NL and AL leagues in 1994.
Bagwell had nine seasons with over 30 home runs, eight seasons with 100 or more RBI, and nine seasons with over 100 runs scored. In six consecutive years, from 1996 through 2001, he reached all three marks in every season. He drew at least 100 walks for seven straight seasons, and had six seasons with a .300 batting average.
Bagwell was also the better player defensively, by quite a margin.
So both in their prime, who would you take?