If Brett Favre returns for a 20th NFL season, you can call him "Grandpa" and not be making fun of his age.
Favre's 21-year-old daughter Brittany gave birth to a son Tuesday, making the 40-year-old Minnesota Vikings quarterback a grandfather.
The little gunslinger weighs in at 7 pounds, 7 ounces.
Grandpa Brett says on his Web site that he and wife Deanna are "very proud" to welcome their first grandchild.
Favre was 19 when he and Deanna -- his girlfriend at the time -- had Brittany in 1989. The couple was married in 1996 and had another child, Breleigh, in 1999.
The NFL says it knows of no other grandfathers among current players.
Favre led the Vikings to the NFC championship game last season and has not yet decided whether or not he intends to return in 2010. He will turn 41 in October.
Information from The Associated Press was used in this report.