Narrator:        This is Science Today. New research has found that stress can increase brain levels of a reproductive hormone called gonadotropin-inhibitory hormone, or GnIH. Integrated biologist George Bentley of the University of California, Berkeley says this hormone essentially puts the brakes on the body's main sex hormone, which can suppress sperm count, ovulation and sexual activity.

Bentley:          Acute stress - it makes sense that we would shut down our reproduction temporarily. If you're a wildebeest out on the plains of Africa, it makes sense not to be investing energy in reproductive behaviors. You need to mobilize your resources to escaping rapidly and it makes sense to shut things down temporarily.

Narrator:        The researchers found that chronic stress has longer-term inhibitory effects on the reproductive system.

Bentley:          So, if these chronically elevated stress hormones are feeding back to this GnIH system, then the GnIH system is something we can target to inhibit the inhibition...and it's early days yet, but this is my pie-in-the-sky idea.

Narrator:        For Science Today, I'm Larissa Branin.