For about 30 percent of couples struggling with infertility, the cause has something to do with the male’s health, according to the American Society for Reproductive Medicine.

Even if your guy’s semen analysis results come back normal, there are still things that could be affecting your chances of getting pregnant.

Not only that, but healthy sperm makes for healthy babies. A study in The Journal of Neuroscience found that children born to men who had experienced stress had a reduced response to stress, something that’s linked to anxiety and depression.

Here, are 5 ways your guy can boost his fertility and increase your chances of getting pregnant.

1. Stop smoking.
If you need one more excuse to quit, here it is. Smoking cigarettes and marijuana can cause oxidative stress and damage your sperm. What’s more, a recent study in the journal Human Reproduction found that smoking marijuana can change the size and shape of the sperm as well.

2.Get to the gym.
“Exercise raises your testosterone and that helps you make sperm,” Danner said. Yet excessive exercise or overtraining can deplete vitamins and stored hormones. What’s more, too much time on a bike or in Spinning class can put excessive pressure on the testicles, so consider taking a break for a while.

3. Cut down on plastic.
Men who are exposed to phthalates, a group of chemicals found in plastic containers and hair products, took 20 percent longer to get their partners pregnant, a study in Fertility and Sterility found. Try to choose glass over plastic and check the Environmental Working Group’s website for safe products.

4. Eat nuts and seeds.
Almonds, Brazil nuts and walnuts are great choices, as are most nuts and seeds, because they’re filled with selenium, zinc and copper which help sperm count. In fact, a study in the journal Biology of Reproduction found that men who ate about 2.5 ounces of walnuts a day improved their sperm vitality, motility and morphology. Ancient grains like millet, amaranth and quinoa are good choices too.

5. Make mushrooms.
Reishi mushrooms strengthen the immune system, are anti-inflammatory and can prevent and treat candida yeast growth in the colon which can make it hard for sperm to function, Fratellone said. You have to eat a lot of them to reap the benefits so ask your doctor about taking a capsule instead. Shiitake and cordyceps are also good choices and can be eaten whole.