Bob Woodward -- Robert Redford RUINED My Sex Life

Bob Woodward was famously portrayed by Robert Redford in "All the President's Men" ... and the legendary journalist says the movie did the same for his sex life that Watergate did for Richard Nixon.

We caught up with Woodward in Washington, D.C. yesterday and asked if having one of the best looking guys in Hollywood play him in the 1976 movie actually helped him score more chicks.

Woodward got a kick out of the question, and then whipped out a funny ... yet sad response.