WIMBLEDON, England — According to the authoritative new book “The Birth of Lawn Tennis” by Bob Everitt and Richard Hillway, when Maj. Walter Clopton Wingfield published the first set of rules for the sport in 1873, the lone illustration showed a mixed doubles match.

Men and women playing together, at both recreational and professional levels, has always been a signature of tennis. Other sports are trying to catch up; the 2020 Olympics will feature mixed events added to shooting, table tennis, swimming, track and field and triathlon. Alpine skiing had an Olympic mixed team competition for the first time this year.

But in tennis, the mixed competition is stagnant. While mixed doubles is still played at the four Grand Slam events, the format has not been added to any of the many combined ATP-WTA tournaments on tour, despite being added to the Olympic slate in 2012. The Hopman Cup, an event each January in Perth, Australia, is the official mixed event of the International Tennis Federation, but it is set to end after next year to make way for a men’s-only competition.

The most telling atrophy of mixed doubles might be seen in the prize money at Grand Slam tournaments. Mixed doubles players have been left behind as singles and doubles players have successfully lobbied for steep increases in prize money.