These early flavor encounters can shape palates after birth. One study in which Mennella and other researchers randomly assigned some of their subjects to drink carrot juice daily in the last few months of pregnancy or after birth, during lactation, found that those women’s children had a stronger preference in infancy for the flavor of carrots than the babies of women who were instructed to avoid carrots and drink water. Another study that had pregnant women eat garlic found a similar effect that persisted into the children’s adolescence.

That said, people develop flavor preferences in many other ways—maybe they were fed a certain food repeatedly as a baby, or observed their parents, siblings, or friends enjoying it during childhood. So even if a taste one has for, say, ice cream and potato chips mirrors one’s diet in the womb, the latter may not have been solely responsible for the former. “When you look at ‘My mother craved this; I like that’—that's association. That doesn’t tell you cause and effect,” Mennella said. “If the mother likes the food and the child accepts the food, they will continue to be fed it, strengthening the preference.”

Whether there’s a biological cause or not, the foods that mothers eat during pregnancy can be imbued with lasting meaning for their children. Layma Murtaza, who works in international development in Washington, D.C., and Kabul, Afghanistan, told me that her mother had a predilection for toasted cheese sandwiches during pregnancy—which Murtaza only learned roughly a decade ago, when she was in her early 20s, after a childhood of enjoying the sandwiches two or three times a week.

Even though she eats much less bread now, the food remains special to her because of what it meant to her mom. “That’s what gave my mother comfort while she was pregnant, and I was her first child,” she said. “I think anything that makes her comfortable is something that makes me happy.”

Ice cream and potato chips inspire similarly warm feelings in Nicholson. "Now that I’ve been in college and away at school and not with my mother every day, sometimes when I eat it I get nostalgia [for] my childhood,” she said. “It makes me think about my mom. It makes me miss her.”

Mennella thinks that this narrativizing is quite powerful. “When these individuals are retelling these stories, it's really bringing them to their past, to their beginning,” she said. “It's the formation of who they are." Whether treasured prenatal foods are treasured because they were among the first flavors someone ever tasted or because warm familial feelings later gave them a mythic status is beside the point: Above all, these foods are something a mother and child shared when they were closer than they’d ever be again.

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