The recent study at Sydney IVF clinic , Australia, found that male fertility begins to decline when they reach their mid-30s, suggesting that biological clocks are found in men as well as women.

So, if you thought only women witness a fall in their fertility levels after reaching late thirties or early forties, you certainly need a rethink. This study suggests that a similar biological fertility clock is also found in men..

"Drops in fertility from the age of 35 have been traditionally thought of as a fact-of-life for women but our study shows the same is true for men," the Telegraph quoted Dr Mark Bowman, the director of the IVF clinic, as saying.

The study team carried out the research on 3,324 men over a four-year period testing their sperm DNA to assess its "reproductive potential". Finally researchers concluded that starting from 35 years of age; there was a significant increase in the proportion of damaged sperm.

According to Dr. Bowman this means that even if a man produces the average of 40 million sperm per ejaculation, many of those sperm will not be able to fertilize an egg normally. By consequence, men who wait until their 40s before starting a family, have a greater chance of their partner having a miscarriage, owing to the poorer quality of their sperm. This man will have a lower fertility potential and be less likely to father a child.