When you go out for your favorite hot drink, your selection might influence whether or not you’ll soon be bringing along someone else to the café. New studies show that moms-to-be should opt for decaf, but a potential Dad should order a double (or triple) espresso.

Brazilian scientists at the American Society for Reproduction in San Antonio, Texas have found that men who drink a few cups of coffee a day are more fertile than men who drink no coffee. The reason is that the caffeine increases sperm motility, which means that it encourages the sperm to swim faster. The faster each sperm swims, the more likely it will reach the egg in time to fertilize it. The study was conducted with men who were already fertile and did not previously have difficulty conceiving. As many as six cups a day can maximize sperm motility, although research has shown that even one cup can have a beneficial effect.

Conventional wisdom has usually influenced women to give up or cut down on coffee when they discover they are pregnant. New research shows that women should cut out the java even before the test shows two lines. According to one study, as little as one cup of strong coffee a day can cut a woman’s chances of conceiving in half, while other studies show that a woman’s fertility is protected up to a three cup maximum.

What’s the reason for the discrepancy? The magic limit in all of these studies is 300 milligrams. Up to this limit, consumption of caffeine seems to have little or no effect on a woman’s fertility. However, caffeine levels in different kinds of coffee vary. For example, very rich drip coffee, the variety often served in restaurants and cafes, has as much as 350 milligrams of caffeine. If you are a woman and want to conceive, it may be safe to drink no more than 8 ounces of percolated coffee at home, which peaks out at 275 milligrams. Instant coffee has less caffeine, between 50 and 200 milligrams for 8 ounces (of course, it depends on how many spoonfuls you add). Despite espresso’s strong flavor and reputation for creating a buzz, two ounces, an average serving, has only 40-70 milligrams of caffeine. The reason is that the extremely high temperature needed to make espresso burns away excess caffeine. Cappuccino, with as little as 50 milligrams of caffeine, is also easy on a woman’s fertility and tempting to the palate. Decaf is the best choice, although it is not completely caffeine-free, with about 5 milligrams of caffeine. However, unless you intend to drink 60 cups a day, decaf will not affect your fertility.

Teas, in general, have less caffeine than coffee. Black teas have as much as 175 milligrams, and green tea has as only about 20 milligrams. However, watch those bottomless glasses of iced tea on summer day; at 70 milligrams a serving, a few thirst-quenching glasses can put you over the limit. The same applies to soft drinks, which have 60 milligrams of caffeine. An occasional cocoa can be an excellent replacement for your morning grind, and at 30 milligrams of caffeine, it is well under the risky limit. One serving of chocolate, also at 30 milligrams, should also have little or no effect.

There is one study that suggests that tea might be beneficial for a woman’s fertility.
The Kaiser Institute in California reports that women who drink as little as a half a cup of caffeinated tea may increase chances of conception. This might be due to the polyphenolic compounds in tea which possibly have fertility promoting effects. However, it has also been suggested that tea drinkers usually have a healthier lifestyle in general, and that other factors might have contributed to successful conception. The study was not carried out with amounts exceeding half a cup, which is still under the 300 milligram limit suggested for potential mothers

Although women who were not heavy coffee drinkers to begin with have claimed that cutting down on coffee has not affected their fertility (they probably were well under the limit in the first place), many women who were heavy coffee drinkers (3cups a day or more) have reported that cutting down or cutting out coffee has helped them to conceive. Of course, if you are a wannabe Dad, do the opposite of your spouse, and drink till you feel a buzz!

Written by: Miriam Metzinger