Math Nerd Figures Out Exact Chances to Conceive a Baby

by Laura Sussely-Pope

In the Spotlight: New Chart Figures Exact Chances of Conception

Richie Cotton is a self-described math nerd. He's also a fan of math and charts. He and his girlfriend are trying to conceive so he compiled a chart to his girlfriend and himself figure out how long it will take them to conceive. Doesn't everyone have a partner like that?

It's pretty well known that women become less fertile as they get older. But how much exactly? Richie Cotton calculated the figures with a chart!

Cotton used data from various sources, including the Journal of Human Reproductive Sciences and Social Fertility to figure out “monthly fecundity rate” (MFD), which in English means the likelihood of getting pregnant each month if you’re having sex without birth.

An average, healthy woman of 25 has an MFD of 25 percent. MFD decreases to 10 percent for a woman of 35. He then put the data in some formulas to plot out the chart.

According to the chart, after two years, nearly all 25-year-old women will get pregnant. The older women get, the less steep their dotted lines get. In other words, the graph visualized what we already knew: It takes longer for older women to get pregnant.

While the gap between 25-year-old women's baby pink line and 35-year-old women's green line is not too bad, the five-year difference between a 40-year-old and 45-year-old is striking.

The same chart for men, on the other hand, would look very different, Cotton says. "From a male point of view, conception is an embarrassingly parallel problem; you can dramatically reduce the time to conceive a child by sleeping with lots of women at once."

Something tells me that would not go over too well with wives and girlfriends!

What do you think about this chart? Do you find it helpful? Have you used our basal body temperature charting tool?

Photo courtesy of