Maybe it's true that love knows no bounds. And when we're exploring space and discovering new alien life-forms, it just makes sense that we're going to have their babies. Here's our nine favorite half-human hybrids.
Spock (Star Trek)
Let's start with the really obvious here. Spock's father is a Vulcan ambassador named Sarek and his mother a human named Amanda Grayson. Much of his character, therefore, is based in the contrast between his two halves, with Leonard Nimoy having said that Spock is ""struggling to maintain a Vulcan attitude, a Vulcan philosophical posture and a Vulcan logic, opposing what was fighting him internally, which was human emotion."
Jack of Hearts (Marvel Comics)
The Jack of Hearts was born Jack Hart, the son of Philip Hart, a human scientist, and Marie, a humanoid extraterrestrial of the Contraxian race. His powers, which include such things as flight and the ability to project heat and concussive force, don't come from his parents, but rather his exposure to "zero fluid," a discovery of his father's.
B'Elanna Torres (Star Trek: Voyager)
B'Elanna, chief engineer aboard the USS Voyager, had a human father and Klingon mother, but her father left for Earth when she was a child, leaving B'Elanna to be raised by her mother. Either due to her childhood or her parentage, B'Elanna was short-tempered and often aggressive, but Roxann Dawson (the actress who portrayed B'Elanna) has said that over the course of the series, the character grows from an "unruly teenager" into a woman.
The titular character in this twelve-issue comic book series written by J. M. DeMatteis is an adolescent boy of human-alien parentage. His mother is a human woman from Brooklyn named Sheila Fay Bernbaum, who takes on the name "Sunflower" during her flower-child days. When she's transported to the alien "zoo," she marries one of her abductors, a member of a nigh omnipotent race called the G'l-Doses. They're essentially glowing orbs of indeterminate largeness who use their power to wreak havoc on the universe, causing war and peace, death and life, with no real modus operandi beyond the delight they derive from the randomness of their actions.
Rystáll Sant (Star Wars)
A dancer for the Max Rebo Band, Rystáll has a Theelin father and human mother from New Bornalex. (It's argued, actually, that due to their greatly varied physical characteristics, that most Theelin are hybrids of one kind or another.)
Deanna Troi (Star Trek: The Next Generation)
Troi is the counselor aboard the USS Enterprise, with a Betazoid mother and human father.
Jason (Superman Returns)
When Lois's son shows up, we're supposed to assume the father is Richard White, her fiancé (and Perry White's nephew). But then Jason starts showing signs of super-strength and Kyptonite sensitivity, thereby implying that (sorry, Richard) Jason is actually Superman's kid. (The current convention that Superman cannot conceive a child with Lois clearly does not apply here.) So, yes. Superman: deadbeat alien father.
Reverend Golightly and the kitten children of Thomas Kincade Brannigan and Valerie (Doctor Who, new series)
In "The Unicorn and the Wasp" (Episode 7, Series 4), the Reverend Golightly is revealed not only to be Lady Eddison's son, but also the product of an affair she had with a Vespiform, a giant wasplike alien. Awkward.
"Gridlock" (Episode 3, Series 3) sees the introduction of a delightful little nuclear family, made up of Thomas Kincade Brannigan, a cat man, his human wife, Valerie, and their children: a litter of kittens. (It's debatable whether Brannigan counts as an actual alien, as he probably counts more as just a highly evolved feline lifeform. It's also debatable whether Brannigan is named after Thomas Kinkade, the "painter of light." Let's hope not.)
Additionally, in the 1996 TV movie, the Doctor himself claims to be "half-human, on my mother's side." But generally speaking, nobody listens to anything the Doctor Who TV movie said.
Hera Agathon (Battlestar Galactica)
Hera is the first known half-Cylon, half-human child. Her father is Karl "Helo" Agathon and her mother Sharon "Athena" Agathon.