|Feral cat colony. Picture in public domain.|
Therefore, if you introduce into a population of feral cats some male cats who can pass on this modified gene then eventually that colony would disappear and in a very humane way.
The technology is called "gene drives". As an alternative to passing on a gene which renders female cats sterile, you could ensure that offspring are nearly always males which would create an imbalance between males and females in a large colony. This also would have the result of reducing the colony's size to the point where it became zero ultimately.
I am convinced that it must have been discussed. It is new technology but I don't recall it being discussed in relation to feral cats. In The Times newspaper date 'gene drive' is discussed in relation to grey squirrels in the UK which have had a decimating impact upon red squirrels as many people know.
A lot of people consider that the domestic and feral cat is an invasive species (like the grey squirrel in the UK) and gene drives are one way of dealing with invasive species. I don't approve of it particularly and neither does the People for the Ethical Treatment of Animals. They dislike it because genetic engineering is unapproved for people and therefore why should it be approved for animals.
Another issue is that it may be difficult to confine this kind of genetic engineering to the target animals concerned. If it spread beyond the targeted species it may have a detrimental impact upon ecosystems.
However, I believe that this risk is being tackled. Like many other people, I am concerned about the plight of feral cats in many parts of the world. They are often abused or live rather short and miserable lives. However, sometimes their lives are quite decent because there are many volunteers running TNR programs in America, for example, which I think is wonderful.
TNR programs, I would argue, are similar to genetic engineering. In the former surgery is employed to make cats sterile and in the latter that objective is achieved through genetic engineering. Both are humane methods or considered so, certainly in relation to alternatives such as mass killing which is employed in Australia.
I would certainly recommend that the Australian government looks at this method of controlling feral cat populations. They have struggled for many years with methods to reduced the number of feral cats on their continent. As it happens, those efforts which are very cruel now seem rather futile and stupid in comparison to the estimated half a billion animals of native species which have been killed in the infamous wildfires which are largely out of controlled in the east of the country.
These fires have arguably been inflamed by global warming and Australia contributes to global warming by being one of the world's major coal mining countries. They export coal to China where it is burnt in coal power stations which contributes to global warming.
Arguably, Australia is in a complete mess with respect to the preservation and conservation of their native species. This is because of the ambivalent approach by their government and because they pursue economic growth at all costs as do most other countries which is very hard to stop in a competitive world. However, global warming is having a devastating impact upon wildlife conservation.