Excluding Julian Bashir and the products of the human Eugenic Wars... do we ever encounter any species in Star Trek that have engaged in significant genetic self-modification or eugenics?

Basically are any other member species of the federation ever shown or said to have engaged in self genetic modification or is it only humans?

Are there any species or colonies inside or outside the Federation shown or implied to do so?

  • Related: scifi.stackexchange.com/q/23016/1234
    – Xantec
    Feb 8, 2019 at 14:52
  • Note that it's only the genetic manipulation of humans that's illegal in the Federation.
    – Valorum
    Feb 8, 2019 at 15:02
  • 1
    If I had a proper computer I’d answer with the Klingons (where their genetic engineering is the in-universe explanation for their appearance differences from TOS to the modern series), and also the Vorta and the Jem’Hadar, which were modified by the Founders for their respective roles. DS9 brings up a lot of genetic engineering, actually...
    – n_b
    Feb 8, 2019 at 15:08
  • In Borderland I believe Phlox indicates genetic modification has been successful on Denobula.
    – 1252748
    Feb 15, 2019 at 3:47
  • @1252748 that's the kinda thing I was thinking of. Now kinda curious whether they ever show any other denobulans in star fleet.
    – Murphy
    Feb 15, 2019 at 11:22

3 Answers 3


Memory-alpha has a section on eugenics.

In Plato's Stepchildren the aliens in that episode are the remnants of the population of the planet Sahndara "who were bred for their self-reliance, contemplation, and longevity".

The only other things it mentions about non-human eugenics are in relation to the Dominion, but that is the Founders acting on other races.


In the Affliction and Divergence two-parter, from Enterprise, the Klingons try to adapt human eugenics attempts to their own species, with nearly disastrous consequences (they accidentally created a plague and the cure resulted in Klingons losing their forehead ridges, explaining why they don't have them in TOS era but do elsewhen).


TNG' Unnatural Selection had the Federation itself returning to the genetic engineering well. The episode creates continuity problems as this exception to Federation law is never explained.

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