Sperm are some of the tiniest cells in a man’s body. They’re responsible for delivering genetic information to the egg, so it has enough information to become a baby. Sperm travel from the “sperm factory” in a man’s testicles to his sperm duct and into your vagina. Then they swim through your cervix and uterus, and eventually reach the end of your fallopian tubes. Here, the sperm will fertilize your egg (if an egg is ready and waiting). Sperm are released by the hundred million, so their odds are good!

How sperm actually works

Unlike women, who are born with all the eggs they’ll ever have, men don’t even begin to produce sperm until they reach puberty. A man’s testes are where sperm cells are created. These young sperm cells then travel into an area of tightly coiled tubes just above the testes, called the “epididymis”. They stay here until they’ve matured.

This whole process takes about 70 days to complete, and happens continuously throughout a man fertile life.

When the sperm cells are mature, some of them mix with seminal fluid (produced by a man’s prostate) to create semen. Semen can then be released from the man’s penis into your vagina. It doesn’t take long for a man to repopulate his sperm, so go ahead and try everyday if you wish – especially when you expect to ovulate. For more information on timing, see Eggs.

Once sperm are in your vagina, they’ll swim up through your cervix and uterus. Neat fact: if there’s an egg present, they’ll pick up the egg’s chemical scent to figure out with of the two fallopian tubes the egg is in!

If there’s no egg, the sperm can live in the woman’s body for up to five days, waiting for an egg.

When the sperm and egg finally meet, the sperm will compete to be first to penetrate the egg’s outer layer. Once inside, the egg will unravel the winning sperm’s densely packed DNA and begin to fuse the genetic material with its own.

Mission completed, the fertilized egg then travels into the uterus to implant!

The most successful sperm have two qualities: they’re great swimmers, and there’s a whole lot of them!

But don’t worry: sperm that only have one of those qualities can still fertilize an egg. (For example, if there’s a huge amount of not-so-great swimmers, or a small amount of terrific swimmers).

10 easy ways to help your sperm

  1. Avoid excessive heat, like hot tubs or saunas.
  2. Limit coffee to one or two cups per day.
  3. Don’t smoke or do drugs, even marijuana. Marijuana can affect your sperm for over two weeks!
  4. Don’t drink more than two ounces of alcohol twice per week. Alcohol is a male reproductive tract toxin, and it’s associated with a decrease in the percentage of normal sperm.
  5. Maintain good eating habits. Fresh fruits, leafy vegetables, and red meat (if possible) can help.
  6. Exercise regularly and moderately (don’t go on any crazy diets).
  7. Antidepressants may decrease sperm counts, so if you’re taking them, don’t worry if it takes a little longer to get pregnant. Be patient.
  8. Be aware of sexual problems and don’t be afraid to ask for medical help. It’s nothing your doctor hasn’t seen before.
  9. Be in good emotional shape. If you’re struggling with feelings of stress, insecurity, or other problems, don’t wait to ask for help! Talk to someone who supports you, or find a therapist you like.
  10. Educate yourself about health and reproduction.