Not really gender, but i do stick with age relation. I just reccently had a mom call for care for her daughter who is 9 years old, she didnt seem to care of the age difference, but I do. I told her I have all younger children ranging from new born to about 3. some 5's but going oof to school soon, she didnt have any issues but for me I have a few, one is to keep ALL kids happy. I find the older they are the more bored (of course) they will get with a younger croud, not to mention that is more on your plate to keep ALL happy. too much work. IMO. not to mention, from a parents point of view I often wonder if they are not turned off more by the age difference rather than the gender difference. I would be concerned if there was a child quite a bit older than mine in a daycare setting for many reason. girl boy shouldnt make too much difference though especially at a young age, they all ussly learn to play together quite well, although.....if I were a mo0m looking for care I guess I would hope there would be at least one other boy or girl for my boy or girl to play with. i.e. what does one 3yr old boy do with say 3 yr old girls all day long? it just would be nice to have a good mix of both gender.