A clever mistake

Today in one of my first grade classes we were reviewing the names of some farm animals that we had learnt in kindergarten. We came to 'sheep' and in the picture I was showing was also a lamb. One of my students said, "Well, that must be lambo, which would be a boy, and if it was a girl it would be lamba." I asked him to explain his statement, whereupon he said 'O's are for boys and 'a's are for girls....my students have lots of experience with gender endings, starting with 'niño' and 'niña' in kindergarten. Though the o's and a's won't forever suffice (wait for mapa and mano and problema and so on!) the concept is well accepted with my students and as in this case, is well understood, even if the words he made up are incorrect. So smart!