Cross-species matings

In a few science fiction series (the Star Trek Franchise being the most notable), humans, can have sex with extra-terrestrial species and produce young. This is, of course, absolutely ridiculous. Even taking into account the possibility of Panspermia, an extra-terrestrial sapient would have less in common genetically with a human than a human does with a daylily.

Species are defined by their inability to cross breed.

Notable products of cross-species matings include:

• Mr. Spock
• Deanna Troi
• B'Elanna Torres
• Sela
• K'Ehleyr
• Alexander Rozhenko