Father's Day is a wonderful time to celebrate the dads of the world, but it is also a good time to talk about men who are trying to become dads.

Some men have fertility issues making it difficult for them and their partner to get pregnant; in fact, male infertility accounts for an estimated 40 percent of fertility problems in couples who have difficulty conceiving.

When it comes to a man’s fertility, a number of common factors can be at play, according to doctors.

Just the thought of having a baby can be stressful. Doctors from The Men's Clinic at UCLA Medical Center said they see men that are not only stressed professionally but then have the added stress that comes along with trying to get their spouse pregnant. It is enough to send couples fighting and not being able to conceive.

Researchers found that men who experienced two or more stressful life events in the past year had a lower percentage of sperm mobility and quality compared with men who did not experience any stressful life events.

Life strains can then lead to weight gain.Overweight or obese men can have lower testosterone and a higher incidence of fertility issues. One potential reason is that larger thighs can increase the testicle temperature affecting sperm health.

Doctors said it is important to do what you can to reduce stress and lose weight if they are issues for you. The Men's Clinic at UCLA, tell their patients to eat, move and sleep

Simple lifestyle changes can make a big impact on a man's over-all and in turn, reproductive health.

Diet

Focus on fresh fruits and vegetables, high protein foods, and foods rich in polyunsaturated fats (like tree nuts, almonds, and walnuts).

Exercise

Men should break a sweat for 30 minutes or more each day. Exercising just once or twice a week is not enough. According to doctors, anything that improves blood flow, heart rate, and metabolism on a regular basis is probably going to translate to better sperm production.

Sleep

Try to get more than six hours of sleep per night. Sleeping recharges their pituitary gland, and the pituitary gland controls sperm production by the testicles. If you are consistently not getting enough sleep, there's a good chance the hormones that control sperm production are also lagging.

Physicians are able to perform a number of tests to determine the root of fertility issues and there are a number of surgical and medical options to repair such issues and help couples reach their fertility goals