And then there are the 'polarized' kittens!
Kittens with access to only vertical (or horizontal) stimuli during their early life will be incapable of seeing lines of the other orientation later in life. Lots of hits refering to these results without actual references to the original research... But here is an original source, that seems to confirm the effect as more than an urban legend: http://www.brain.riken.jp/bsi-news/bsinews29/no29/research2e.html