Sperm quality reduces with age
Men waiting longer to have children could have a significant impact on the health of their offspring, a new study shows..
A study from the University of Otago has found sperm deteriorates as a man ages, which can lead to a range of health problems for his child.
It is recognised a woman's age can contribute to health problems in the child, but it has been less clear whether the age of a man had similar effects.
The answer is yes, says the study's lead author Dr Sheri Johnson.
"While female age is well known to have negative effects on fertility, reproductive success and the health of offspring, the influence of male age on a couple's fertility has been largely neglected," she said.
Not only did older sperm increase the risk of miscarriages and other pregnancy complications, it increased the likelihood of the child having autism, Down syndrome, epilepsy and schizophrenia.
It could also be a big factor in the couple's infertility and could lead to an increased use of fertility treatment such as IV, she said.
The findings were important because many couples were waiting longer to have children, Johnson said.
The study analysed 90 existing studies on male fertility and found consistent findings across them that the quality of a man's semen declined as he aged.
Semen quality is used to show how fertile a man is.
The study did not try to find the rate of decline, but Johnson said existing studies showed it could begin as early as 35, with a consistent downward trend from then.
The specific problem with older semen was lower volume, poor sperm performance, and increases in malformed and DNA-damaged sperm.
Johnson said greater focus on the quality of sperm - including the ratio of DNA-fragmented sperm cells and their ability to swim - could lead to better fertility outcomes for older couples.
"These are likely more accurate and consistent predictors of a man's fertility status than commonly clinically measured traits such as semen volume, sperm concentration and total sperm count," she said.