https://www.sciencedaily.com/releases/2018/11/181126105455.htmhttp://archive.is/ESgLJSperm count 50 percent lower in sons of fathers who smoke
Studies have repeatedly linked maternal smoking during pregnancy with reduced sperm counts in male offspring. Now a research team has discovered that, independently of nicotine exposure from the mother, men whose fathers smoked at the time of pregnancy had half as many sperm as those with non-smoking fathers.
Unlike the maternal ovum, the father's gametes divide continuously throughout life and mutations often occur at the precise moment of cell division. We know that tobacco smoke contains many substances that cause mutations so one can imagine that, at the time of conception, the gametes have undergone mutations and thereby pass on genes that result in reduced sperm quality in the male offspring.
Most newly occurring mutations (known as de novo mutations) come via the father and there are also links between the father's age and a number of complex diseases. In addition, researchers have observed that smoking is linked to DNA damage in sperm and that smokers have more breaks in the DNA strand. Children of fathers who smoke have been reported to have up to four times as many mutations in a certain repetitive part of the DNA as children of non-smoking fathers.
