class=”imagewrap has-source-dimensions”
data-crop-type=”wide”
style=”
–source-width: 5202;
–source-height: 2926;
”
>

More than 30 states have medical marijuana programs — yet scientists are only allowed to use cannabis plants from one U.S. source for their research. That’s set to change, as the federal government begins to add more growers to the mix.
Drew Angerer/Getty Images
hide caption
toggle caption
Drew Angerer/Getty Images