Quote from Marshall in Cleaning House
Ted: Wow. Loretta really lied a lot to her kids.
Lily: Well, she's not alone. Whenever Marshall was acting too hyper, his mom would suddenly decide he was "sick" and give him cough medicine until he passed out.
Marshall: I'm pretty sure that's what stunted my growth. I hit 6'4" in the fifth grade, and then I just stopped.