(covers information from several alternate timelines)

B'Elanna Torres, a hybrid split into Klingon and Human halves
A hybrid or mixed species was the end result of mixing two or more different species in the biological process of reproduction. Klingons referred to hybrids derogatorily as a mongrel. (VOY: "Barge of the Dead", "Prophecy") Spock was also derogatorily referred to as a half-breed on a number of occasions. (DIS: "If Memory Serves"; TOS: "What Are Little Girls Made Of?", "This Side of Paradise", "Day of the Dove")
Biological aspects
Because of the common genetic ancestry of most of the species of the Milky Way Galaxy by way of the ancient humanoids, many species were able to interbreed with or without the help of genetic technology. (TNG: "The Chase")
According to Doctor Phlox, Humans and Vulcans were quite similar. (ENT: "Demons") In fact, Bethany, a Human/Skagaran hybrid, was one of the first known hybrids encountered by Humans from Earth, confirming that such interspecies breeding was possible. (ENT: "North Star")
Societal aspects

Tora Ziyal, a female Bajoran/Cardassian hybrid
In some cultures, children who are born as a result of interspecific relations were rejected by the society of both races. For example, Bajoran/Cardassian hybrids were often rejected by both Bajorans and Cardassians. (DS9: "Indiscretion", "Return to Grace") This was, however, also often the same treatment received by Cardassian orphans as well. (DS9: "Cardassians")
During the mid-22nd century, before such things were commonplace, those behind Terra Prime, such as John Frederick Paxton, believed that Elizabeth, a test tube baby-hybrid of a Human and a Vulcan was "a cross-breed freak," asking, "How many generations before our genome is so diluted that the word "Human" is nothing more than a footnote in some medical text?" (ENT: "Terra Prime")
Personal aspects

Spock, a Vulcan/Human hybrid
As noted above, Spock, a Human/Vulcan hybrid, had many personal demons when it came to his being.
In 2266, he shared with Doctor Leonard McCoy that "being split in two halves is no theory with me, Doctor. I have a Human half, you see, as well as an alien half, submerged, constantly at war with each other. Personal experience, Doctor. I survive it because my intelligence wins over both, makes them live together." (TOS: "The Enemy Within")
Examples of interspecific reproduction
Aenar
Bajoran
- Bajoran/Cardassian
- Mika and Dukat's child
- Tora Ziyal
- Bajoran/Cardassian/Human
Betazoid
- Betazoid/Human
- Anita Pierce
- Walter Pierce
- Ral's mother
- Deanna Troi
- Thaddeus Troi-Riker (¼ Betazoid, ¾ Human)
- Kestra Troi-Riker (¼ Betazoid, ¾ Human)
- Ian Troi
- Kestra Troi
- Betazoid/Human/Klingon
- Betazoid/Tavnian
- Lwaxana Troi and Jeyal's son
Caitian
- Caitian/Unknown species
Cardassian
- Cardassian/Bajoran
- See above
- Cardassian/Bajoran/Human
- See above
- Cardassian/Kazon
Human
- Human/Angel I native
- Human/Bajoran/Cardassian
- See above
- Human/Betazoid
- See above
- Human/Betazoid/Klingon
- See above
- Human/Boraalan
- Human/Daliwakan
- Human/Denobulan
- Human/Greek god
- Human/Ikaaran/Two unknown species
- Human/Klingon
- See below
- Human/Ktarian
- Human/Napean
- Human/Ocampa
- See below
- Human/Romulan
- See below
- Human/Skagaran
- Bethany (¼ Skagaran, ¾ Human)
- Human/Trill
- See below
- Human/Vulcan
- See below
- Human/Vulcan/Terrellian/Rigelian
Klingon
- Klingon/Betazoid
- See above
- Klingon/Human
- K'Ehleyr
- Alexander Rozhenko (¾ Klingon, ¼ Human)
- B'Elanna Torres
- Miral Paris (¼ Klingon, ¾ Human)
- K'Ehleyr
- Klingon/Romulan
- Klingon/Trill
Ocampa
- Ocampa/Human
Romulan
- Romulan/Human
- Romulan/Klingon
- See above
- Romulan/Vulcan
- Oh
- The Romulo-Vulcans, including Shira
Talaxian
- Talaxian/Mylean
- Talaxian/Mylean/Vulcan
- Tuvix, a fusion of Tuvok and Neelix, was created by a transporter malfunction with hybridizing flowers.
Trill
- Trill/Human
- Trill/Klingon
- See above
Vulcan
- Vulcan/Human
- Vulcan/Romulan
- See above
- Vulcan/Talaxian/Mylean
- See above
Appendices
See also
- Amalgam
- Bastard
- Unnamed hybrids
Background information
In an initial story outline of TOS: "Charlie X", Charles Evans was referred to as a Human/Ferndok hybrid, since his mother was a Ferndok (a species which, during the episode's development, was later renamed Thasian).
Apocrypha
In the novel The Ashes of Eden, Kirk discovered the colony world of Chal, a planet briefly colonized by the Romulans and Klingons during an alliance, populated by genetically-engineered Klingon-Romulan hybrids.
External links
- Genetic hybrids at Memory Beta, the wiki for licensed Star Trek works
- Hybrid (biology) at Wikipedia
- Half-breed at Wikipedia