Why rounding odd font sizes to even?

Today I started implementing a design that had some copy text with font size 17px. My fellow web developer told me that we should round that to 18px and more in general that we should not use odd font sizes. He thought this is because the text may look better.

So my question is: do text with even font size look better than odd? Or what is the reason to round odd font sizes as given by design to even in the css?