Kitten wasn't the only one offended.
When you start saying the only way to get brown eyes from a blue-eyed parent is for infertility, that's pretty awful.
See the caculator linked below.
Yes, strange things happen --- like a mutation.
But a TRUE blue --- with all four allels being blue --- almost always results in a blue-eyed child. Period.
The simplest, easiest, explanation is the most likely: the eyes are genetically hazel, appearance notwithstanding.
Here is a comprehensive calculator:
http://genetree.com/resource/traitsPaternityTest.php