(CNN) -- Roger Federer is putting fatherhood ahead of next month's French Open.
The world No. 4 says being at wife Mirka's side for the birth of their third child is more important than competing at the clay court grand slam in Paris.
Federer has played in a record 57 straight grand slam tournaments. The last major he missed was the U.S. Open in 1999.
But the 17-time grand slam winner told reporters at the Monte Carlo Masters: "It's a priority for me to be there (at the birth) to support my wife.
"I've played enough tennis matches. Missing a tournament or missing a match wouldn't change anything for me."
Federer and Mirka became parents to twin girls Charlene Riva and Myla Rose in July 2009.
The 32-year-old revealed on Twitter on Christmas Eve that the Swiss sweethearts were expanding their family in 2014.
But Federer would not reveal his wife's due date or whether the couple were expecting another set of twins.
The world No. 4 is currently competing on the Monte Carlo clay after a two-year absence from the principality's Roland Garros warm-up event.
"As we don't know when it [the due date] is going to be yet, I'm happy playing at the moment," he added after his 6-0 6-2 win over Marin Cilic on Wednesday.
Federer said it was too early to say whether he would definitely play at the French Open, which begins on May 25th.
The former world No. 1 won the French Open title in 2009 to complete the rare feat of winning all four grand slam trophies.
If he opts to skip the tournament he could miss out on a big pay day.
Organizers of the French Open announced that the prize fund has increased by $4m in 2014. The total prize money on offer is now $34.6m.
The winners of the men's and women's singles titles will each receive $2.3m, which is a 10% increase on last year's prize pot.