Let me ask you a question: What if you had the power to make it so that not a single human being in the whole world ever suffers of Cystic Fibrosis ever again? Or Hemophilia? Or even Huntington’s Disease? Would you do it?

If you could change anything in your own body, like choosing your own gender, your eye color or even adding characteristics of other animals, like the Japanese "Nekomimi" and fictional beings, like the green skin and antennas of Dragon Ball's Namekusei's people, would you wish for that?

Or if you could make sure your children would be hundreds of times smarter, faster and stronger than any human who has ever lived and with immune systems so strong that not even the deadliest of viruses, bacteria or even poisons would do any harm to them, would you want that?

It is indeed quite wondrous to imagine the benefits that genetic manipulation would have in the future of mankind. A technology that is already undeniably on our doorstep, since genetically engineered babies have already been born in China, yet there is also no denying the ethical implications of taking evolution into one's own hands.

Several religious people have already openly spoken against genetic manipulation, as it would be the same as "playing gods", yet the benefits of fully eradicating genetic deadly diseases and still allowing the bearers of said illnesses to die for the sake of religions a lot of people might not follow, including those at death's door, is equally unethical.

Yet, what if someone were to do it in a global scale without the possibility of consent in the first place, to eradicate something like a gene that causes a human to become a maniacal rapist for example?

Think of it like this, if there is a gene that causes a human, be it male or female, to feel sexually excited at the face of sexual violence to the point of becoming a mass rapist, would such a gene not have spread a lot among human kind considering the whole lawless period of human history since prehistoric times?

A gene that forces others to get pregnant or impregnate someone against their will, evolution wise, thinking only in terms of nature which by itself does not consider ethics, only results, would definitely increase a race's reproduction and have a high rate of passing on to the next generation. As the amount of mass rapists in the current world does not go over the mark of 50% of the global population, it is safe to say it would not be a dominant gene, yet as medieval war have a lot of records of several soldiers raping the population of the losing side, it definitely is not a rare gene either, so it would be believable to say that quite a considerable fraction of the human race must bear at least a fraction of said gene that induces a person towards rape, dormant or not, just by considering how frequent it happened throughout history and still happens nowadays.

Now, consider that to erase said rape inducing gene, a group of scientists develops the following in a black ops site:

Making use of an extremely highly infectious, genetically engineered, air and water borne mutated version of HIV or a similar virus that affects and changes a cell's DNA, employing techniques similar to CRISPR, Cas9, 12a or 13 and then triggering a strong mutation throughout the body to quickly enact the genetic changes to all of a human's cells without killing the host, they create a pandemic virus capable of infecting the whole of the human race across the globe and enact the same genetic manipulation to the whole race.

In this case, it would be to make sure that not a single human being alive carries that "rape gene", which in turn would make so that no human being is ever born carrying such a gene as well. And the same could be done for something like pedophilia, quite possibly.

But what if someone uses the same virus and technique to make it so that every human being has the same skin color? Or completely erases the existence of "hair" from the human genome? Or worse yet, completely extinguishes the existence of a sexual gender, either making every male become a female or the opposite?

Are the pros of possibly eradicating some of the most heinous crimes and psychiatric pathologies from the future history of human kind greater than the cons of the possibility of completely extinguishing the existence of a human characteristic like skin color variations, hair as whole, a gender, which would possibly mean the extinction of our race or whoever knows what someone could design it for maliciously?

And how can we prepare against a group doing so even if illegally, hidden by governmental or military protection or even in international waters?