Navratilova, who came out as a lesbian in 1981, said sporting culture is very different from the relatively gay-friendly world of entertainment.
“In the entertainment guys have an easier time coming out than women. In the sports world we have had a lot more women coming out than men,” she said.
While she acknowledged the difficulty of coming out in a team sport, Navratilova wondered why few players of individual sports had come out, and why there were no out tennis players currently competing.
“We know they are there, but they are so far in the closet I don’t know who they are,” she said.
Considered by many to be one of the greatest tennis players of all time, Navratilova said she has given up millions in sponsorship and endorsement over the years because of her honesty.
While there are numerous out women tennis players, the only male tennis player to have come out is Francisco Rodriguez of Paraguay, who came out in 2008 after retiring. At the time, Rodriguez said he would have become an outcast if he came out during a tennis tour.
Born in Czechoslovakia, Navratilova sought political asylum in the United States in 1975 at age 18, becoming a US citizen several years later.
She has been involved in LGBTI activism since coming out, and in 1992 was involved in a lawsuit against a ballot proposition in Colorado to deny gay men and lesbians legal protection from discrimination.
Navratilova has been publicly critical of retired Australian tennis champion Margaret Court, now known for her opposition to marriage equality and her anti-gay views generally.
Navratilova has been in a relationship with former Russian beauty queen Julia Lemigova since 2006.