I really hope not. My GCSEs are awful, I'm embarassed to put them in! Then again, I took them 10/11 years ago. Thankfully I've improved somewhat with age, and I've received a first. The result is a fairly lopsided CV.
I've considered taking a maths GCSE just to even things out in case people do ask, but I don't tend to mention them unless required. Applying to masters courses was nice, no GCSEs haunting me!
In my interview with Newcastle med school this year they even commented on my 'bizarre' application, heh.