World number one Roger Federer's daughters are less than 48 hours old but bookmakers on Friday had already posted odds on the twins winning Wimbledon.
British bookies Ladbrokes were offering 100-1 for either Charlene Riva or Myla Rose to win the grasscourt title just a day after Federer's wife Mirka, 31, gave birth to the tots.
The twins, whose Swiss father has won a record 15 grand slam titles, were also 25-1 to claim one of the four slams with all bets based on either doing so before their 25th birthdays.
The girls, who were born at a private clinic in Switzerland on Thursday, are 50-1 to win a grand slam as part of the same doubles team and 200-1 to take the Wimbledon doubles crown.
"The twins certainly come from good tennis stock. If they are half as good as their dad they will still be a potent force on the court," said Ladbrokes spokesman Nick Weinberg.
American Andy Roddick, who the 27-year-old Federer beat in last month's Wimbledon final to claim his 15th grand slam, sent a message from his Twitter page about the twins.
It read: "Wimbledon women's champs in 2029-2040 .... the Federer girls: congrats to the new parents!"
Grand Slam: 大满贯