Male infertility is rising worldwide, but this rise is not inevitable as many of the factors causing it can be reversed with lifestyle changes or medication. This includes causes such as obesity, drug, alcohol and tobacco use, some prescription medications and intensive horse riding, motorcycling or bicycling.
Drugs, alcohol and tobacco are the leading causes of reversible fertility issues among men. For example, tobacco inhibits the sperm’s ability to attach firmly to an egg, which is an essential step in achieving fertilisation. Tobacco doesn’t make the attachment completely impossible, but according to a study by Phillip Morris it does lower the chances by up to 75%. Smoking can also damage sperm’s DNA, meaning that where pregnancy does occur the child has an increased risk of genetic abnormalities.
Obesity is another issue, and is a substantial problem in countries such as the United States, where being obese is especially prevalent. While there have not been any studies carried out to try to link BMI directly to male infertility, many such studies have shown a link with female infertility. And working from first principles, we know that being overweight affects your health, which in turn affects sperm health. Especially when coupled with another factor such as tobacco or alcohol, it is therefore likely that obesity can reduce fertility.
Medication-induced infertility is often easily fixed; your doctor can generally prescribe an alternative medication which does not have the same side effect. But some treatments, such as chemotherapy or radiation, are more difficult to avoid. In these cases you may need to wait until the treatment is over before sperm can return to normal, especially if the treatment area is located near the testes.
Strenuous riding can also be difficult to avoid if your job depends on it. Motorcycle couriers, for example, or jockeys cannot simply stop riding. But if the riding is for pleasure, cutting down the frequency, and riding for shorter periods should both be possible, and may be enough to improve your fertility.