We shouldn't turn the trend around though. Most of our environmental problems including most likely this one, are caused by our overpopulation and increased welfare. We just need too many resources, this can't continue.
So if people organically decide (or due to this sperm count thing are forced) to have fewer kids, this is really a brilliant thing for the planet.
Anti-human garbage take IMO. The planet is not more important than humanity. Vast swathes of this planet are uninhabited by humans, people have been predicting for generations that too many people would destroy civilization and the planet and none of it has come true (see the Population Bomb "predictions" section on Wikipedia for a laugh)
This narrative has been popular, especially among wealthy, educated, people for a long long time. But most of it is hogwash.
So if people organically decide (or due to this sperm count thing are forced) to have fewer kids, this is really a brilliant thing for the planet.