# At what age should I get pregnant?

## A mathematical model helps women make a decision ‘too important’ to trust to feelings

Thinking of having a baby but can’t decide when or even if? A professor and his Ph.D. student have come up with a mathematical system to help women make decisions that are “too important to simply go with one’s feelings,” says Ralph Keeney and his student, Dinah Vernik of Duke University’s Fuqua School of Business. So Keeney and Vernik have devised a two-hour questionnaire that pushes women to think far into the future and deep into their heart’s desire. At the moment, “the model helps one woman at a time,” Keeney said. But soon they hope to have a workable version available to the public, online.

Each answer a woman gives is translated into a number. Amy Dalton, a 30-year-old Canadian now working in Hong Kong, participated in the model and remembers being asked questions like, “Assuming you have a child right now, what’s the blow to your social life going to be?” Dalton thought about the question and decided, “I’d reduce it from 70 per cent down to 10 per cent because this kid would eat up all my time and I’d have no life.” On the questionnaire, Dalton jotted the number 10 on an X-Y axis. When her questionnaire was done, it looked like algebra, and the data was fed into a computer.

Keeney insists “the system isn’t complicated because of the math. You put in the uncertainties. You personalize it. The computer does the crunching and it will let you know what’s important to you.” Every woman, he adds, “knows this is a very difficult problem. Somebody has to decide how various factors relate to each other, in this case, how a child has a detrimental impact on a woman’s career.”

In the case of another young woman, Keeney was surprised that the computer results so thoroughly contradicted what the woman said she wanted. Before the questionnaire, the woman said she’d like to have a baby at age 45. The computer said, “Have the baby at 20.” “That’s surprising to me,” said Keeney, adding, “I have a thought on why that might occur.” According to Keeney, the same woman forecast, “When I’m 45, I’m going to be at the top of my career and that’s important to me.”

“When you’re a doctoral student, you can deal with a child pretty well,” he said. “You almost never have anything due this week. It’s due in two years. You can work tons but if your child is sick in the morning, you don’t have to work that day. This means the better time for her to have a baby is much earlier.”

Dalton, who’s originally from Toronto, said before she answered the questionnaire that she didn’t want to have children: “I know the research that shows that once a couple has a kid, the happiness in the couple drops off. I’m thinking, why would you ever want that?” At the beginning, she says, “it was really difficult. I was thinking, ‘What the hell, 30? 40? 50?’ I’d never thought about it so systematically,” she said. “To go through and think, ‘Okay, when I’m 60, how much would I want a kid? And when I’m 50, how much would I want a kid, and how much would my career actually matter then?’ All of these things I previously thought were unquantifiable, now all of a sudden I had to throw out a number.”

When the questionnaire results came back, Dalton couldn’t believe it. “They ran my data and they told me I should start trying to have a baby right now. I said, ‘You’ve got to be kidding me! Show me the numbers! This is ridiculous!’ ” She called her mother in Toronto with the crazy news. “My mom got extremely emotional. She started telling me how it was to see me as a child enjoying things for the first time, and how that’s something I might never get unless I start now.”

One of Dalton’s professors has had two babies since she’s been at Duke and “you know,” says Dalton, “I’m in her office and she pulls out this breast pump and I’m like ‘What the hell is that?’ I feel squeamish just thinking about it.” On the other hand, she’s intrigued by how her mother went about it. “She had me quite young,” says Dalton. “She’s 52. We talk on the phone. We have a great social relationship.”

Dalton isn’t into infants, she says. She rates having one at 10 per cent “because it can’t do anything but sit there and cry.” But she admits she might one day enjoy the company of having adult children just like her mom does. In that case, “I would have to start now!” she says. So who knows. “A year from now I might have my biological clock ticking, then I should redo all the graphs.”