Keep cool: for optimum sperm production, the testicles need to be a couple of degrees cooler than the rest of the body. Avoid tight underwear and jeans, and excessively hot baths and saunas.
Think about your job: occupations that involve sitting for long periods, such as long-distance lorry driving, or exposure to environmental chemicals such as paints or pesticides, may affect sperm quality. If this is an issue, discuss it with your work supervisor.
Manage stress: stress doesn't cause infertility, but excessive anxiety can sometimes upset the menstrual cycle. Try to reduce stress levels and give yourself time to relax.
Take folic acid: all women trying for a baby should take a supplement of 400mcg of folic acid a day to help prevent birth defects such as spina bifida.
Check drugs: certain prescription drugs can reduce the chance of conception. If you're taking regular medication, talk to your doctor.
Marijuana and cocaine can affect sperm counts.
Things you can't change
Not all factors affecting fertility are within your control.
Women
For women, the following may affect conception:
Ovulation problems: sometimes, women don't ovulate (release an egg each month) or do so only occasionally.
Reasons include:
Polycystic ovary syndrome (PCOS), in which numerous small cysts develop on the ovaries and ovulation is erratic.
The side effects of some medications, such as anti-inflammatory painkillers, chemotherapy and radiation treatment (for example, for cancer).
Premature ovarian failure (early menopause).
Hormonal imbalances