Rates of birth defects such as achondroplasia (short stature) and autism is higher among children with older fathers. Single and multi gene disorders

"It is curious that although sperm have been around since the beginning of time, we know so little about what is in them, and what makes them tick, er, swim. So scientists spend a lot of their waking hours trying to compare the structure and content of the proteins of sperm in various species, in order to understand their evolution and origin. For instance, the mutated DNA in the genes of the sperm of older fathers is believed to cause many genetic diseases. It is almost as if a man’s biological clock accelerates mutation in sperm cells in his early ’30s."


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Birth Defects Higher Among Children with Older Fathers
Older men have an increased risk of having a child with abnormalities, new research suggests.

The common belief is that there is no age limit for men when it comes to fathering a child. Unlike women who undergo menopause, men do not have a fixed “andropause”. However, this view is being challenged as new evidence shows that the rates of birth defects such as achondroplasia (short stature) and autism is higher among children with older fathers.

A recent study carried out at a large Israeli army database found that children of men over 40 were 5.75 times more likely to have an autism disorder than those who had fathers under 30. Another Israeli study suggested that the risk of schizophrenia in children is almost double if the father is in his late 40s.

Prof Sheena Lewis, a consultant in reproductive medicine at Queen's University Belfast, said that as men get older their sperm DNA becomes more fragmented. By the time a man is 50, the cells that create a man’s sperm have replicated up to 800 times, creating many possibilities for error.

According to Prof Lewis:

The impact of the father smoking is even worse than the mother smoking (you can't repair damage caused in sperm DNA)
Viagra can affect fertility by causing the sperm to travel too fast
Cannabis us slows sperm function, resulting in a reduction in fertility
She also warns about the damaging impact of modern lifestyle and environmental factors.







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