Your money shot may be a blank. About 15 per cent of couples have trouble conceiving, and at least a third of the time the guy's sperm is at fault, according to the National Institutes of Health.
So get busy: sperm quality peaks in winter and early spring, an Israeli study found, and low-stress weekends offer your best chances of success.
Dr Ashok Agarwal, head of reproductive medicine at Cleveland Clinic, explains how four lifestyle changes can improve your baby-making odds.
Related: 7 Signs Your Semen is Healthy and Strong
Sperm are not perfectly shaped little tadpoles. In fact, 90-plus per cent of the average guy's swimmers may be too deformed to penetrate the egg. Excess free radicals may be to blame, Agarwal says.
Consuming foods rich in the antioxidant lycopene is one solution, Harvard scientists say. (For a quick boost, eat tomato sauce: A quarter cup has 8,500 micrograms.)
A typical ejaculation can contain 15 to 150 million sperm. To maximise your potential payload, you need to work up a sweat outside the bedroom, says Agarwal.
In fact, Harvard researchers found that men who worked out the most had a 33 percent higher sperm count than those who exercised the least. That's because gym time helps burn fat while boosting testosterone.
Your sperm must carry out their mission in 12 to 14 hours; that's how long the egg, once it's released, remains viable. Success can depend on their swimming speed.
So help them out: put down the smartphone. In a Cleveland Clinic study, men who used their phones more had decreased sperm mobility, perhaps because of these phones' electromagnetic waves.
Those swimmers need to stay alive - and your choice of lube matters. Even lubes that are touted as "all natural" may contain chemicals that are acidic or alkaline enough to poison your mini-Phelpses.
In fact, some brands can wipe out 72 per cent of your offering in 30 minutes, say researchers in Australia. Save your sperm with a blend designed for procreation.
This article was originally published on MensHealth.com