Judy Woodruff:

All this week, we're looking at the impact of the wave of marijuana legalization.

One of the key questions is whether marijuana is generally more potent now and whether that poses an increased health risk for some people. It's also coming amid debates surrounding the larger benefits and risks of marijuana.

For our Leading Edge segment, Miles O'Brien sifts through the science around what's known and not known about these claims.

It's part of a close look at The Green Rush around the country.