There are a lot of factors as to why reproduction is important, Sage. I have a few things in mind that can give you ideas on how to construct your essay.
I'll need the ideas a lot. I just feel like the decrease of reproduction and population will help the Earth, but I also need something that contradicts that ideology.
Human reproduction is important because it serves as the solution to continue a bloodline and most important of all, generations.
Without the humans reproducing, there would be no one to operate the invented machineries to dissipate incoming space objects that might impact Earth causing huge damage.
Without reproduction, animals will become less and less, and that might lead to them becoming endangered until they're extinct.
With things being extinct, we won't have any sorts of food and production of objects won't be continued anymore causing world hunger and poverty.
Overall, reproduction maintains a balance between birth rate and death rate and it helps the ecosystem going.