Prenatal Allergies Prompt Changes.

• Position: SEXUAL DEVELOPMENT

A single allergic reaction during pregnancy prompts sexual-development changes in the brains of offspring that last a lifetime, suggests research from Ohio State University, Columbus.

Female rats born to mothers exposed to an allergen during pregnancy acted more characteristically "male"--mounting other female rodents, for instance--and had brains and nervous systems that looked more like those seen in typical male animals. The male offspring also showed a tendency toward more female characteristics and behaviors, though the changes were not as significant.

"The study shows for the first time that an allergic reaction in a mother could alter the sexual development of its offspring," says lead author Kathryn Lenz, assistant professor of psychology. 'This allergic response is enough to make the female brain look like a male's brain, and that's something that endures throughout its entire life."

Previous research has shown that insults to the immune system-including stress, infection, and malnutrition--can change brain development. These shifts in sexual behavior help researchers understand the interplay between allergens and brain development, and highlight that early life immune activation could be a source of normal variations in female behavior.

Moreover, these...