Original sentence: They also argue that it would improve the overall health of populations due to heterosis (or "hybrid vigor"), although no empirical evidence for this has been presented.While some people want to preserve the "racial purity", others think that, quite contrary, it is desirable to increase genetic diversity of human populations, arguing that it would increase the range of talents available to society
Edited sentence: While some people want to preserve the "racial purity", others think that, quite contrary, it is desirable to increase genetic diversity of human populations, arguing that it would increase the range of talents available to society; also, it would improve the overall health of populations due to heterosis (or "hybrid vigor"), although no empirical evidence for this has been presented