It takes two to tango:

Average sperm counts fell by a third in a study of 26,000 men between 1989 and 2005, increasing their risk of infertility.

Dr Hassan Bakos, Deputy Scientific Director at Repromed, an infertility research and treatment provider said the findings, released last month and previously reported by Motherpedia confirm previous research over the past 70-80 years that sperm counts are declining in many countries across the world.

“The decline in the study occurred progressively throughout the 17-year period, confirming previous reports of the same nature,’’ Dr Bakos said.

The latest research was conducted in France, but it has global implications.

“Something in our modern lifestyle is causing this. We still do not know which are the most important factors, but the most likely are obesity and environmental exposures.’’

About one in 20 men are infertile in Australia and on average one in six Australian couples has difficulty achieving their dream of having a baby.

“It’s important to try to understand the issues that impact on fertility,’’ said Dr Bakos.

“A lot of pressure is still put on the female when trying to conceive, with many people still assuming that infertility is largely due to female factors alone.’’

Dr Bakos said that when it comes to “lifestyle” factors, would-be fathers should not leave maintaining a healthy lifestyle up to their female partner.

For men wanting to start a family with their partner in 2013, here are some things to think about:

• Smoking: Smoking is one of the leading causes of damaged sperm and it may also have an impact on the health of the child if the father smokes around the time of conception.
• Obesity: being obese is now known to have an impact on sperm health and subsequent pregnancy establishment.
• Alcohol: regular alcohol consumption can impact on sperm quality and function. 
• Age: various studies have suggested that older men have reduced sperm quality and take longer time to establish a pregnancy with their partner.
• Laptops: sitting for long periods with the laptop on the lap can also lead to overheating of the testicles.
• Occupation: jobs that involve long periods of sitting, including driving, can lead to poor quality sperm due to overheating of the testicles.

For most couples pregnancy occurs naturally within 12 months of trying to conceive. Infertility is defined as the inability to conceive after one year of unprotected intercourse, or the inability to carry pregnancies to a live birth.