February 12, 2011 10:40AM EDT

Everyone's Going To Be Hitting The Sheets On February 18 — Find Out Why!

If you want to give your baby the best birthday ever — 11.11.11 — then head to bed four days AFTER Valentine’s Day! Experts explain why.

Couples have been bombarding fertility doctors with the same unique question — how can I guarantee to have a baby on the luckiest day of the year? “They want to know when to have sex to have a baby on November 11,” says Dr. Jamie Grifo, program director of the New York University Fertility Center. “11-11-11 – people really want that birth date for their baby.” HollyMoms, does the date you give birth matter that much?

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Dr. Grifo explains to CNN how couples can make their baby birthday wish come true: A woman who conceives February 18 will have a November 11 due date, provided she has a regular 28-day cycle. But of course conception is not an advanced science. Since cycles vary and most pregnancies aren’t exactly 40 weeks, conceiving a child anytime in the next week or two could get the coveted 11-11-11 digits for your little one. Valentine’s Day sex, for example, could very well land you a baby on November 11.

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The next chance to have a baby born on a date with all six numbers being the same is November 11, 2111. Whoa!