Research presented at a recent European Society of Human Reproduction conference showed that miscarriage rates increased when the male partner was older than 35, while pregnancy rates fell among men over 40.

Andrew Kan, of IVF Australia southern Sydney, said new French research showed the age of males was a significant issue in fertility.

Dr Kan said with the average age of patients at the Kogarah-based centre now 36, it was time to educate the public about the role a man's age had on conception.

He said the new findings added to existing evidence that showed male fertility started to dip at an earlier age than once thought.

Dr Kan said studies had shown DNA damage in sperm increased markedly after the age of 35.

''IVF Australia is working to improve semen analysis tests to help identify men with sperm quality problems and most effectivetreatments,'' he said.

Dr Kan said the causes of male infertility would be discussed at a free information evening to be held on Monday at 6.30pm.

Details: IVF Australia southern Sydney, St George Private Hospital, Level 3, South Street, Kogarah. Phone: 1800111483.