Any reason not to put egg yolk in muffins?

[Tatties]

The recipe I have for oatbran muffins says to use 2 egg whites. I hate waste though and want to put the yolk in as well. Any reason not to? Sorry I have no common sense when it comes to cooking...

Usually only reason to put whites only in is for low-fat versions. Putting yolk in won't affect how the muffin turns out. Perhaps you could use the white in the muffin and scramble the yolks for breakfast/lunch/tea.