Researchers investigated whether men or women have fewer children. Using international datasets, they demonstrate that imbalances in population structure, particularly an increasing proportion of men, affect male fertility. While men used to have higher fertility than women globally, this has reversed, and women have and will have a higher fertility rate than men. The scientists offer recommendations to counteract the social implications of this trend.
There is one way that “one man and one woman” wouldn’t be true, and that’s the trans community. Then again, I’m pretty sure the article isn’t thinking about that.
That’s already a small enough community, and so few members of that community become parents, that I agree it seems unlikely to be a factor in any broader research.