I had this mistaken gender issue happen SO often when Hootie was a baby. Like 2:1, people thought she was a boy. Now, I am not the kind of mother who dressed her daughter in all pink and ruffles and those funky little lacy headbands or scotch-taped a bow to her head. So on days when my child was dressed in something you could only describe as "unisex", it stands to reason that the populus at large could take a 50/50 stab and think she might have been male. But when she's dressed head to toe in pink? Or when she's got two little pony tails sticking up off the sides of her head like Shrek ears, with little ribbons on them? HOW can a person say, "HE's so cute?!" It is a stretch, I know, to assume that just because her darling little face is so delicate and feminine, that everyone else can see that and surmise she's female. I know I have never mistakenly called a male child female or vice versa, so I know it is possible to deduce this by looking at their little faces. But in the event that a person isn't on the same wavelength that gives me this ability, HOLY COW PEOPLE, LOOK AT THE CHILD'S CLOTHING! And if it is still somewhat ambiguous, tell the parent, "You have a darling baby" or "Your child is just precious!" You don't have to associate a gender to such a comment!
I have to assume it is just another annoying form of ignorance, that goes along with other forms of ignorance when random strangers try and interact with children they do not know. Like when people go to touch the baby. HELLO, that is RUDE. Generally speaking, I don't go up to other people's children and TOUCH them. That is an invasion of that child's space. Or, people coming straight at me with their hand to touch my belly when I was pregnant. I thought I was a lumbering ox those last few months, but come at me with your hand, you stranger, and I'll show you how fast I can move! I cannot tell you how many bullets I dodged in that arena, and how many times I had to tell people, "I am guessing you meant no harm, but it JUST isn't appropriate to attempt to touch a person's belly that you do not know, without permission." And people generally get OFFENDED by comments such as this. As though I am supposed to just endure this, for fear of hurting their feelings. What about MY feelings?