sentences:  A 2017 review found that while severe health effects are associated with higher paternal age, the total increase in problems caused by paternal age is low.While paternal age has increased since 1960–1970, this is not seen as a major public health concern.The genetic quality of sperm, as well as its volume and motility, all may decrease with age, leading the population geneticist James F. Crow to claim that the "greatest mutational health hazard to the human genome is fertile older males".