The world governing body for swimming has added mixed-gender swimming relays to its events, which will be in place for a major international meet for the first time at the 2014 short-course world championships.
According to NBC Sports, two women per country could be on the program at the following world championships in 2015 in Kazan, Russia with FINA also saying that mixed relays could be added to the Olympics at some point, but that step has not been taken yet.
The report said that mixed relays at World Cup events, the Youth Olympics and, famously, at the Duel in the Pool meet between the US and international stars had already been held.
Australian Olympic champion Libby Trickett went faster than the women's 100-meter freestyle world record in the leadoff leg of the 4x100 free relay at the 2007 Duel in the Pool, but it didn't go into the record books because she did it swimming against Michael Phelps, the report added.