Cloning for Colonization? In the three seasons of TOS, we see many extras and guest stars reappear in different roles, but, one obvious in-universe explanation is cloning. Maybe humanity could not meet the high demand for people to support the massive human colonization suggested in the series. We see many colonies and even whole planets populated with billions of humans. I think it unlikely that this could occur only over ~200 years of warp flight. Assuming natural births could not fully meet the demand for people, human culture started making test tube babies. If you are going to make a human for colonization, you may as well select human genes from quality individuals that give preferred characteristics. Cloning became perfectly acceptable with no prejudicial treatment of these individuals evident in the show. Several clones have attained high status such as: Admiral Fitzgerald and Commodore Barstow Commodore Robert Wesley and Cmd. Giotto Capt. Ronald Tracey and Dr. Simon Van Gelder Lt. Cmd. Ann Mulhall and Dr. Miranda Jones (cloned and genetically altered for telepathy but also resulted in blindness side effect) Number One and Nurse Christine Chapel even Capt. James T. Kirk and George Samuel “Sam” Kirk Not to mention several crew members (the Leslie’s, Galloway’s, Martine’s, and a number of Red Shirts that were killed to reappear later.) The fact that the cloning topic was never commented on in any episodes is because it was just normal to see clones. In a later TNG episode, cloning was then out of vogue, but it showed that the technology was available in the TOS timeframe. What are your thoughts on the possibility that cloning is common in TOS?