Something's happening to alligators in Florida's Lake Apopka. Male alligators born in this lake contaminated by manmade chemicals are showing dramatic changes in their reproductive systems. Today, there is growing evidence these chemicals are disrupting development in other wildlife too--but are humans also at risk?

In this report FRONTLINE explores the endocrine disruption hypothesis. It's an alarming new theory which posits that certain hormone-mimicking chemicals can disrupt the body's chemistry and lead to cancer, genital deformities and lowered IQ.

Delving into what science is learning, FRONTLINE looks at recent wildlife studies showing grave damage to certain species' reproductive systems and talks to the scientists involved in animal research in the field and in the lab.

The report also chronicles the impact of Theo Colborn's 1996 book "Our Stolen Future" - which brought national attention to the endocrine disruption hypothesis - and tracks Long Island N.Y.'s breast cancer alarm which prompted Congress to mandate that EPA screen and test to detect endocrine disrupting chemicals. Almost overnight, the endocrine disruption theory gained the force of law with this new legislation. But, did policy get ahead of science?

FRONTLINE gives a careful hearing to scientists like Dr. Stephen Safe who point out there's no solid evidence yet linking manmade chemicals to human damage, and EPA scientist Linda Birnbaum, who notes the hype about the new theory has made reasonable scientific discourse difficult.

In a debate sure to go on for years, with polarized views and conflicting science, the experts agree that only time will yield the data which conclusively can prove or disprove the endocrine disruption hypothesis.