There's also technique.
I got a whole lot stronger on hills when I learned to focus on making my stroke efficient all the way around the circle -- "round and round, not up and down" was what the lady said on the video we were watching doing an indoor ride in February. I remember physics class and learning that the forces work best if they're pushing perpendicular, so I practiced... and it really made a difference on hills.
Your friend might really be trying to encourage -- get you to accept that it's okay not to be Queen of the Hills. Still, the whole philosophy that talents are Set In Stone holds a whole lot of people back (including the good athletes, who are sure it's their talent behind success, not technique and hard work).
When I added the Xtracycle extension to my bike, alas, I was no longer the person who charged by people on the uphills. Now I'm the one lagging (unless it's a really long hill)... and my ego misses it... but I can always get out the 7.5FX if I *want* to and whoopeeee!:P