The headquarters of the Centers for Disease Control and Prevention (CDC) is currently collecting semen from hundreds of men especially in the United States in order to figure out how long the dreaded Zika virus lasts in the bodily fluid.
The virus can be transmitted sexually, and it's been known to linger in semen long after a man's fever, rash and itchy eyes have gone away.
If a man has the virus in his semen and has sex with a woman who is pregnant or becomes pregnant, the baby could be born with devastating neurological birth defects.
The CDC has been recruiting for two months and some 40 men who've had Zika have volunteered to donate their semen.
So far, there have been more than a thousand cases of Zika in the United States, and that number is expected to grow.
There have been 14 cases of sexual transmission of the virus, according to the CDC, although some experts think the actual number is higher.
The CDC currently recommends that men who've had Zika use a condom or abstain from sex for six months after their illness.
That advice is based on studying the semen of just three men who had Zika, which is why the CDC is doing this larger study.