Stress is known to affect a person's present and future with a host of health-related problems, but what if it could also affect our offspring? A new study has found that higher levels of stress in mice, even before conception, could cause a gene associated with stress to appear more in offspring.

"The systemic similarity in many instances between us and mice raises questions about the trans-generational influences in humans as well," the researchers said in a press release. "If until now, we saw evidence only of behavioral effects, now we've found proof of effects at the genetic level."

The researchers used female mice that were 45 days old - an age equal to human adolescence - and exposed some to minor stress, including changes in temperature and daily routine, for a week. The ones that weren't exposed to stress acted as the control group.

The researchers checked the ova of these mice before they conceived, and found that those exposed to stress had enhanced expression of the CRF-1 gene, which is associated with the body's stress-control system, and appears increasingly when the brain is stressed. Once the mice gave birth, before they could interact with their newborns, the researchers tested each pup for CRF-1-all those that had stressed mothers also showed enhanced expression of the gene.

But the researchers wanted to see if the gene appeared in higher amounts later on in life, so they exposed all the offspring to stress when they reached adulthood. They found that expression of CRF-1 was dependent on three factors: The sex of the offspring, the amount of stress that they endured, and the amount of stress the mother went through. Stressed female offspring that had mothers that also endured stress showed the highest levels of CRF-1 than any other group.

"This is the first time that we showed that the genetic response to stress in rats is linked to the experiences their mothers underwent long before they even got pregnant with them," the researchers said.

"We are learning more and more about inter-generational genetic transfer and in light of the finding, and in light of the fact that in today's reality many women are exposed to stress even before they get pregnant, it's more important to research the degree to which such phenomenon take place in humans."

A 2008 study found that women were more likely than men to feel sad and anxious because of stress, The Guardian reported. They were also more likely to reflect on their feelings about a stressful situation. Dwelling on these negative feelings made it harder for women to work through stressful situations, the researchers said in the study.

"If you think about it, sadness and anxiety are very passive emotions," author of the study, Dr. Tara Chaplin, told The Guardian. "If you're sitting there feeling sad and anxious, you're not as likely to problem-solve and be assertive. That could be a problem in the workplace."


Zaidan H, Leshem M, Gaisler-Salomon I. Prereproductive Stress to Female Rats Alters Corticotropin Releasing Factor Type 1 Expression in Ova and Behavior and Brain Corticotropin Releasing Factor Type 1 Expression in Offspring. Biological Psychiatry. 2013.

Chaplin T, Hong K, Bergquist K, et al. Gender Differences in Response to Emotional Stress: An Assessment Across Subjective, Behavioral, and Physiological Domains and Relations to Alcohol Craving. Alcoholism: Clinical and Experimental Research. 2008.