Circa 1992 in the Star Trek Timeline there was a war that was based on altering human genetics. This was called the Eugenics War. It was a war between genetically altered humans and natural humans. Natural humans won the war and made genetic tampering illegal at this time as is explained later in Star Trek DS9 when issues of Doctor Julian Bashir's genetic enhancement are brought to light. In that episode Julian's parents arrive on DS9 and his father is forced to serve a 2 year sentence for allowing Julian to be genetically altered as a child and hiding it for so long (something like 22 years). My point is that if genetic alteration is illegal why wasn't the criminality of it brought to light. The Eugenics Wars timeline I am pretty sure was established in the Original Series. My point is that Unnatural Selection is an affront to humanity and peace and the crew doesn't even bat a lash at this concept.
One more plot hole I will point out is that Transporter Chief Miles O'Brien is a commisioned officer in TNG - a lieutenant, having obviously gone to the academy, traversed being a cadet, and gotten his officer's commision as an ensign. Later before the show begins he must have been promoted to Lieutenant. The plot hole is that later on in DS9 then Chief O'Brien makes sure to point out on many occasions that he is a non-commisioned officer Chief on many occasions and that would mean that even an ensign such as Nog could tell Chief what to do. How is it possible that a Commisioned officer somehow lost his commision and became an NCO? Could he have resigned his commision, left starfleet, and returned as an NCO? As is proved by Chief Engineer Argyle(He appears in 2 episodes - Ep 5 - "Where No One Has Gone Before" is one) in the 1st Season of TNG, and Chief Engineer Lt. Geordi La Forge in the 2nd Season you CAN be a commisioned officer and still be the Engineering Chief.
The third and biggest plot hole in this episode is that Dr. Polaski is beamed up in the end and she doesn't carry the "infection" which they were so kind to point out earlier in the episode that the "infection" couldn't be filtered out through the transporter system and they failed twice to do so, resulting in Dr. Polaski's "infection" in the first place. Did something change? Otherwise the whole crew would have been affected by the "infection" and it would be the end of the series since everyone you know would be dead. Because they never fully explain how the disease is passed from one host to another you can't really give it full credence as a plot hole, but it was convenient to the story let's put it like that. It seems to me by the conclusion of the episode, considering they saved Darwin IV, they had mastered this condition so why blow up a perfectly good starship when you can transport their crews corpses into space, give her a scrub and tow the derelict back to a starbase or call in a tug as was done once in Season 1 - surely the immune Data could accomplish this if nothing else. Energy and materials are free in the ST Universe but humanoid labor to assemble the materials is not free and they would have to consider it their greatest asset. To give up all that labor in one photon torpedo burst just doesn't seem prudent to what an actual captain might do, in today's navy or in the navy of the future.
Lastly, they bring to light the fact that Geordi really doesn't need to wear the visor(banana clip), he just wants to. By DS9 a mere 6 years later they completely rebuild Vedek Bareil in Season 3 Episode 13 "Life Support" as he wastes away a piece at a time. When the get to the brain they decide to let him die because he would be nothing but machine at that point. So if they can rebuild an entire human being and prosthetics are in a golden age, then why does Geordi ever start with a visor on this show? It was something that they realized and quickly scrambled to explain later in the series. If I was not correct in this, it would have never been brought up in the show, it would be accepted fact.
In conclusion I found this episode to be poorly written, and a poor fit to the Star Trek Universe and in my personal opinion. It's plot holes are so large you could pilot a Galaxy Class Starship thru them. Although Dr. Polaski has more character than Dr. Beverly Crusher, I find her to be more of a liability to the show(bones has been done before and better thanks), and I will be glad when she is finally gone.
One more thing, the laptop screens are like 4 inches thick on this episode. You tend to see thru the facade when you see things like that. It's really hard to make a show about the future because everything that happens in the world would have to be reflected in the future as well. For example in the first season I recall Cpt. Picard telling Cmdr. Riker to "download that file to sick bay" when he would clearly have to UPLOAD it. Also they don't have bluetooth! When they sit together and talk it's funny because they could've used the internet to look up whatever they wanted and had the computer read it back. Instead they use Data for this function of giving the audience/crew information. It's just kind of funny is all. TNG is a great show, just not so consistent with the lines it predecessors and it's progeny laid out.
One more plot hole I will point out is that Transporter Chief Miles O'Brien is a commisioned officer in TNG - a lieutenant, having obviously gone to the academy, traversed being a cadet, and gotten his officer's commision as an ensign. Later before the show begins he must have been promoted to Lieutenant. The plot hole is that later on in DS9 then Chief O'Brien makes sure to point out on many occasions that he is a non-commisioned officer Chief on many occasions and that would mean that even an ensign such as Nog could tell Chief what to do. How is it possible that a Commisioned officer somehow lost his commision and became an NCO? Could he have resigned his commision, left starfleet, and returned as an NCO? As is proved by Chief Engineer Argyle(He appears in 2 episodes - Ep 5 - "Where No One Has Gone Before" is one) in the 1st Season of TNG, and Chief Engineer Lt. Geordi La Forge in the 2nd Season you CAN be a commisioned officer and still be the Engineering Chief.
The third and biggest plot hole in this episode is that Dr. Polaski is beamed up in the end and she doesn't carry the "infection" which they were so kind to point out earlier in the episode that the "infection" couldn't be filtered out through the transporter system and they failed twice to do so, resulting in Dr. Polaski's "infection" in the first place. Did something change? Otherwise the whole crew would have been affected by the "infection" and it would be the end of the series since everyone you know would be dead. Because they never fully explain how the disease is passed from one host to another you can't really give it full credence as a plot hole, but it was convenient to the story let's put it like that. It seems to me by the conclusion of the episode, considering they saved Darwin IV, they had mastered this condition so why blow up a perfectly good starship when you can transport their crews corpses into space, give her a scrub and tow the derelict back to a starbase or call in a tug as was done once in Season 1 - surely the immune Data could accomplish this if nothing else. Energy and materials are free in the ST Universe but humanoid labor to assemble the materials is not free and they would have to consider it their greatest asset. To give up all that labor in one photon torpedo burst just doesn't seem prudent to what an actual captain might do, in today's navy or in the navy of the future.
Lastly, they bring to light the fact that Geordi really doesn't need to wear the visor(banana clip), he just wants to. By DS9 a mere 6 years later they completely rebuild Vedek Bareil in Season 3 Episode 13 "Life Support" as he wastes away a piece at a time. When the get to the brain they decide to let him die because he would be nothing but machine at that point. So if they can rebuild an entire human being and prosthetics are in a golden age, then why does Geordi ever start with a visor on this show? It was something that they realized and quickly scrambled to explain later in the series. If I was not correct in this, it would have never been brought up in the show, it would be accepted fact.
In conclusion I found this episode to be poorly written, and a poor fit to the Star Trek Universe and in my personal opinion. It's plot holes are so large you could pilot a Galaxy Class Starship thru them. Although Dr. Polaski has more character than Dr. Beverly Crusher, I find her to be more of a liability to the show(bones has been done before and better thanks), and I will be glad when she is finally gone.
One more thing, the laptop screens are like 4 inches thick on this episode. You tend to see thru the facade when you see things like that. It's really hard to make a show about the future because everything that happens in the world would have to be reflected in the future as well. For example in the first season I recall Cpt. Picard telling Cmdr. Riker to "download that file to sick bay" when he would clearly have to UPLOAD it. Also they don't have bluetooth! When they sit together and talk it's funny because they could've used the internet to look up whatever they wanted and had the computer read it back. Instead they use Data for this function of giving the audience/crew information. It's just kind of funny is all. TNG is a great show, just not so consistent with the lines it predecessors and it's progeny laid out.