Martina Hingis was 16 years, 6 months old when she gained the #1 ranking in women's tennis in March, 1997.
Lleyton Hewitt is the youngest male to reach tennis world number one.
Lleyton Hewitt (19th November 2001)
20 (Lleyton Hewitt)
I think either Boris Becker or Layton Hewitt. I think they were 17 years old.
Lleyton Hewitt, an Australian tennis player, is famous for ranking World No. 1 at age 20, making him the youngest male tennis player to ever rank World No. 1. He has competed in various tournaments as well.
Best Male Tennis Player ESPY Award was created in 1993.