By Nick Georgandis

April 14 - Former world doubles No.1 Jim Grabb turns 49. Grabb was No. 1 in both 1989 and 1993, and won two Grand Slam titles in men's doubles - the 1989 French Open with Patrick McEnroe and the 1993 US Open with Richey Reneberg. He was also on the US Davis Cup in 1993 which lost in the first round to Australia. In all, he won 23 doubles titles with a gaudy 23-3 record in finals.

April 16 - Former world doubles No.1 Patrick Galbraith turns 46. Galbraith was a three-time All-American at UCLA before going pro and was ranked No. 1 in October of 1993. He won two Grand Slam titles, in mixed doubles alongside Elna Reinach at the 1994 US Open and with Lisa Raymond at the 1996 US Open. In 11 years on the tour, he won 36 men's doubles titles, but never a Grand Slam, despite reaching the finals of Wimbledon twice. A true specialist, Galbraith played just three singles matches in his entire pro career.

Belarus' Natasha Zvereva, half of one of the greatest women's doubles tandems of all time, turns 42. Zvereva won 18 Grand Slam women's doubles titles between 1989 and 1997, winning each Slam at least three times and completing her career doubles Slam in 1993 when she won the Australian Open for the first time. In total, she took Australia thrice (1993-94, 1997); the French Open six times (1989, 1992-95, 1997); Wimbledon five times (1991-94, 1997); and the US Open four times (1991-92, 1995-96). She also won two mixed doubles Grand Slams - the Australian Open in 1990 and 1995. She won the first two of those doubles titles with Larisa Savchenko, one with Pam Shriver, one with Martina Hingis and the other 15 with Gigi Fernandez, who Zvereva was inducted into the International Tennis Hall of Fame with in 2010. In singles, she reached No. 5 in the world in 1989 and is a bit of an ignomious footnote. Zvereva reached the finals of the 1989 French Open and was beaten by Steffi Graf 6-0, 6-0 in 32 minutes, the shortest final in Grand Slam history.

Spain's Conchita Martinez, the 1994 Wimbledon champion and three-time Olympic medalist in women's doubles, turns 41. Martinez won 55 singles titles and 41 doubles titles in her 19-year career, defeating Martina Navratilova for her lone Grand Slam crown. She would be ranked as high as No. 2 in the world in October of 1995, and as high as No. 7 in doubles, where she won silver medals at the 1992 and 2004 Olympics, along with a bronze medal in 1996.

April 17 - France's Jo-Wilfried Tsonga, currently ranked No. 8 on the ATP tour, turns 28. Tsonga has been ranked as high as No. 5 in the world (2012) and has reached three Grand Slam semifinals - the Australian Open in 2010 and Wimbledon in 2011 and 2012. Overall, he has 10 singles titles and four in doubles, winning a silver medal in men's doubles at the 2012 London Olympics.

April 19 - BBC sports luminary and 1976 French Open champion Sue Barker turns 57. Barker was ranked as high as No. 3 in her professional career which spanned 12 years. She won 11 singles titles and 12 doubles titles, the biggest when she defeated Renata Tomanova at Roland Garros while just 20 years old.

Career Grand Slam singles winner and current world No. 2 Maria Sharapova turns 26. Sharapova has won 28 WTA singles titles and has spent 21 weeks in her career atop the WTA rankings. She won her first Slam at Wimbledon in 2004 at age 17, and has since added titles at the US Open (2006), Australian Open (2008) and French Open (2012). She also won the silver medal at the London Olympics in 2012, losing to Serena Williams in the final. Off the court, Sharapova has been one of the most marketable female athletes of her era, endorsing Nike, Canon cameras, Motorola, Tiffany and Land Rover. She has also done photo shoots for Sports Illustrated's Swimsuit edition as well as FHM and Maxim.