Star Trek: 10 Things You Didn't Know About Dr Leonard 'Bones' McCoy

It's easy to miss because it was only mentioned in one episode, but Bones actually had a daughter named Joanna McCoy. She was originally going to pop up as a love-interest for Kirk in the Original Series episode The Way To Eden (which definitely would've shook up things between him and McCoy), but that character was replaced with Irina Galliulin.

The only time she was actually mentioned was in the Animated Series episode The Survivor. A Vendorian shapeshifter came aboard the Enterprise disguised as the famed space-philanthropist Carter Winston, and McCoy thanked the imposter for saving his daughter, Joanna, ten years prior.

Carter Winston was one of the wealthiest private traders of the time. He was a generous guy, so he used his private fortune to go around the galaxy helping needy people. The people of the planet Cerberus went through a catastrophic crop failure in 2259 that left them at risk of starvation. Luckily, Winston came along and used his wealth to feed the population, saving everyone on the planet, including Joanna McCoy. Soon afterwards though, Winston mysteriously went missing.

The Vendorian imposter revealed that Winston's ship had crashed on the planet Vendor, and he had died shortly after. However, the Vendorian was becoming more and more like Winston every day, so it's possible that he went on to continue Winston's good deeds after being taken away by the authorities at the end of the episode.