Popping may not be 100% accurate but it's our most effective way of sexing babies. I feel like if a suspected female don't pop after 3 or 4 times it's got to be female. You just have to know what you are doing when it comes to popping. If it pops male then you're done sexing that one. I have had babies with the taper that i would have swore were females and they popped male. The visual thing is only effective in adults. The first thing i do is look at them and then i pop to see if i get the same conclusion.