And you thought 21st-century moms were neurotic.

Being pregnant in 2017 means memorizing long lists of what not to do. Along with smoking and drinking, expectant mothers are told to avoid more innocuous activities like eating raw alfalfa sprouts, getting gel manicures and doing sit-ups. All of this is hard to keep track of, as shown by online pregnancy forums full of panicked posts from moms-to-be. (“Please tell me other people have eaten alfalfa sprouts when pregnant & you are fine!!!” concludes one such post on What to Expect. The first commenter’s response: “WHAT!?!?!? We can’t eat those either?!!?!?”)

But as difficult as modern pregnancy can be, at least expectant moms now have to police only their diets, beauty regimens and workout routines. In the 16th through early 18th centuries, doctors instructed mothers who wanted healthy pregnancies to control something a lot more slippery: their very thoughts.

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This wasn’t a vague link between, say, getting angry during pregnancy and having an colicky child. Doctors literally believed women could reshape their unborn children’s bodies with their minds. In her 2005 book “Mass Hysteria: Medicine, Culture, and Women’s Bodies,” Rebecca Kukla, a professor of philosophy at Georgetown University, gives some examples: “Some of the most common claims were that cravings for strawberries or other fruits would cause birthmarks shaped like those fruits…fright by a bear would cause a hairy child; being startled by a hare would cause a harelip, or cleft palate…” If a mother had “lascivious thoughts” while pregnant, her child might be born intersex, with both male and female genitalia.

As Kukla points out, in half of cases the trigger for these changes isn’t just any old thought?—?it is a desire, whether for food or sex. Pregnant women were offered an implicit choice: Suppress those desires, or risk literally marking them on your children. This framework also set up a mother’s “wayward or weak nature” as the cause of congenital disabilities we now know are mostly caused by genetic or environmental factors. It also absolved men of all blame for characteristics that society construed as “abnormal”?—?which, thanks a lot, patriarchy.

(It should be noted that this belief pathologizes not just female desire, but disability, as well. Unfortunately, this aspect comes through in Kukla’s writing, which uses words like “deformity” and even “monstrosity” to describe disabilities and disabled people?—?a reminder that we in the 21st century still get plenty of things wrong, too.)

The idea that women had to quash their desires to be good mothers fit in well with old-school, patriarchal ideals of female passivity. That might be why the belief persisted in the popular imagination long after doctors gave it up. In the late 19th century, John Merrick, the so-called “Elephant Man,” performed at circus sideshows around Great Britain and Europe, where spectators gawked at his enlarged skull and large flaps of rough, wrinkly skin. The true cause of his symptoms is still unknown to science, but Merrick himself had a good explanation for it: his mother being frightened by a circus elephant while she was pregnant.

Today, few people believe that an expectant mother’s food cravings or “lascivious thoughts” have any impact on her unborn child. However, that doesn’t mean that women today are free of pressure to think or feel a certain way while they’re pregnant. If pregnant women in the 16th century were told to avoid strong emotions, pregnant women in the 21st century are encouraged to feel one, and only one: joy. In a New York Times article about depression during pregnancy, which affects around 15 percent of expectant mothers, Columbia clinical psychology professor Andrew Solomon notes:

Much of the stigma around maternal depression…seems to focus on women who fail at joy, often suggesting that such women are heartless. How can anyone not be swept up by the momentousness of producing a child who will give her life purpose?

Solomon goes on to point out that the guilt that many women feel about depression during pregnancy can keep them from seeking necessary mental health treatment, which can actually lead to adverse health outcomes for both mother and baby.

From the 16th century to the present day, society’s tendency to tell pregnant women to think and feel a certain way generally does more harm than good. It’s time to accept that pregnancy creates huge, complex changes in women’s lives and bodies?—?and necessarily creates huge, complex emotions, too.