1. Ejaculate regularly
Evidence shows that men who ejaculate regularly (every two or three days) have healthier sperm than men who ejaculate too frequently or who try and save up sperm in an attempt to increase the numbers of sperm in their ejaculate. For the best chances to conceive, have intercourse two or three times per week and don't masturbate in between time!
2. Don't smoke
The chemicals in cigarette smoke can cause extensive damage to the sperm DNA so stopping smoking will lead to healthier sperm. However, since it takes about three months to produce a sperm, men should stop smoking well in advance of trying to conceive with their partner.
3. Go to GU Medicine
Some sexually transmitted infections can either damage sperm, or cause fewer sperm to be produced or ejaculated. Also, if you have an STI you can infect your partner and cause damage to her fallopian tubes. So go and get screened. Remember some STI's such as Chlamydia are asymptomatic and so you don't always know you are infected.
4. Don't take steroids
Men who go to the gym to get that muscular chiseled physique, and take steroids to help them along the way, can damage their testicles and make them produce less sperm. Although the effect is usually reversible, it can take several years to recover.
5. Be a healthy weight
Men with a Body Mass Index above 30 are at risk of having lower sperm counts than men with a BMI under 30. Getting back into the normal BMI range is the best thing for healthy sperm production.
6. Eat fresh fruit and vegetables
Sperm are prone to attack by free radicals produced by the body and this can damage sperm DNA. Men can protect their sperm by eating their quota of five portions of fresh fruit and vegetables each day. These are full of antioxidants such as vitamin E and studies show that they can protect sperm from damage
7. Don't leave it too late The DNA in the sperm of older men is not as good as that found in the sperm of younger men. This is because as men get older, more genetic errors creep into the sperm production process. This means that, all things being equal, older men will find it harder to get their partners pregnant, if they do they are more at risk of having a miscarriage and any child born is more at risk of having a medical problem affecting their genes.