Stolen Goods: Do Lefties "Break Out" More Than Righties?

In an old, but still relevant article, Rany Jazayerli of Baseball Prospectus tackles the question of whether or not southpaws develop later than their right-handed counterparts. The data is aplenty if you want to sift through it all, but the conclusions are thus:

There is simply no compelling evidence that southpaws develop any more slowly than right-handers do...

...lefties, as a whole, were not any worse than the right-handers, and in some cases were better...

Maybe a good percentage of left-handers have a breakout season around age 26, but that's only because a good percentage of all pitchers break out at that age. Yes, there are many examples of left-handers who didn't reach their full potential until their late 20s, but there are just as many examples of right-handers who took just as long.