A group of American scientists concluded that the spermatozoa of older men develop more slowly than those embryos that have arisen from the sex cells of young men, reports the Daily Mail. The results of this study were presented at the annual conference of the American Society of Reproductive Medicine, held in San Antonio, Texas.

As a comparison, scientists noted that spermatozoa of men older than 50 years develop 35 percent slower than younger men under 35 years of age. In addition, embryos originating from the sperm of older men late reach the blastocyst stage when the embryo is attached to the uterine wall. In young men, this process takes 4.3 percent less time. In the course of the study, scientists analyzed video recordings on which the development process of over 3.5 thousand embryos was taken, which were taken from 527 heterosexual pairs. Earlier reported that experts called the key danger of late paternity.