If Valentine's Day brings sex, why aren't there more November babies?

Every year on my birthday, which falls on November 10th, my father likes to remind me of the day I was conceived: Valentine’s Day. That particular year, he recounts, the holiday was rainy and cold and there was a Hershey’s chocolate bar involved. *Shudder.*

Along with traumatizing me, this annual walk down memory lane left me with the impression that I was not alone—that there must be tons of little Valentine’s miracles like me, and yes, probably even a spike in the birthrate every November.

But when I stumbled on a dataset ranking the popularity of every birthday in the calendar year, I was surprised to learn that not only is mid-November not a popular time to give birth—it’s a comparatively unpopular time.

The data came from Harvard Kennedy School professor Amitabh Chandra, who specializes in health policy research. Published in 2006, it was based on birthdays from 1973 through 1999, so it could use updating—for now, though, it’s the most recent available.

Back to the revelations. When ranked from 1 to 365, with 1 being the most popular birthday and 365 being the least popular, November 14th is only the 263rd most popular day to be born. And if you look more broadly at November 6th through November 21st, none of the birthdays in that stretch rank above 147th most popular. (It turns out September is the most popular month for birthdays, nine months after the winter holiday season.)

So if Valentine’s Babies are not actually a cultural phenomena—what gives? Are we not having sex on Valentine’s Day? If not, what’s getting in our way? Or if we are, why aren’t there more babies? Given that more than half of pregnancies in this country are unplanned, I knew the answer was more complicated than birth control—so I took these questions to a sex therapist, a biological anthropologist, and an economist for answers.

First, let’s start with the basics. To have a lot of babies, you need a lot of sex, right?

Depending on who you ask, the numbers support the notion that people are, in fact, getting it on on Valentine’s Day. In a recent survey conducted by SKYN condoms, which polled more than 5,000 men and women, 73% of millennials reported having sex last Valentine’s Day. But I call foul. Anyone who has ever lived through the holiday (single or coupled) can you tell that it does not always go off without a hitch—and for many of us, it definitely does not end with a bang.

Stephanie Buehler, a psychologist and sex therapist in Newport Beach, California, told me that, in reality, she tends to receive more distressed phone calls the week before and after the holiday. Yes, fraught with expectations of love and romance, Valentine’s Day often invites the nemesis of sexual bliss: pressure and anxiety.

For many couples, the holiday can be like an unwanted mirror, forcing you take stock of your relationship and ask yourselves: Are we on the same page here? “Valentine’s Day comes, and it’s sort of a let down,” she explained. “Couples go through the holidays together and now they’re faced with the grim reality of things that are not going that well in their relationship. So whatever they left behind in October and November, now they have to deal with it.”

But it’s not just holiday pressures that may curb wild baby making, according to biological anthropologist Helen Fisher.

Fisher told me that she isn’t surprised we don’t see a birth spike in November. For one, she says, biologically, November births are not adaptive. If you harken back to more primitive times, being born in November meant being a helpless newborn heading into the coldest part of the year (in some regions), when food was scarce and parents weren’t getting as much exercise. It’s not a good time to give birth, says Fisher. So if anything, our hardwiring is actually disinclined to conceive in February—if you believe in evolution’s power over our modern-day impulses.

But perhaps more relevant, Fisher also told me that she doesn’t believe the cultural forces of the holiday are enough to get us into bed. The holiday is focused on romance—gifts, sweets, and dinner—not sex : /. Combine all these factors, and you start to see the cracks in my fantasy of an army of Valentine’s Day babies.

Finally, I spoke with Joshua Gans, an economist and author of Parentonomics: An Economist Dad Looks at Parenting—who wasn’t shocked that Valentine’s Day wasn’t a super popular day for conception, either. “If there’s one day when there wasn’t going to be an unplanned pregnancy? It’s Valentine’s Day,” Gans told me. After all, you plan the dinner, the date, the gift—you’re definitely planning for contraception.

A New York City blackout, on the other hand? That’s a different story.

Now, say you are determined to conceive a baby on this day—Buehler, the sex therapist, did offer some advice for skirting the pitfalls of the holiday. “Just relax about the whole thing. It’s a holiday fraught with peril,” she says. If you’re in a relationship, “There should be a philosophy that every day is Valentine’s Day, so that you’re not starting with a cold engine on February 14th. You want to be loving all year, that way you don’t have time to make up.”

Or you could really get down to brass tacks and take the advice of sex columnist, author, and podcaster Dan Savage, who tells his audience: F*ck first.

“Remember, kids,” he wrote on The Stranger in 2014, “a romantic meal doesn’t put you in the mood for a good f*ck but a good f*ck builds up an appetite for a romantic meal.”

Whatever your Valentine’s Day plans, may you have my father’s luck.

Cleo Stiller is a digital producer covering the intersections of sex, tech and culture. Words to live by: get your money’s worth.