I think its the 3 combined (latex - only the sperm getting through the 1 hole - and surviving the spermicide) sways that makes a good girl sway.

Which means that the amount of sperm is much less and the theory is that supposed more girl sperm will make it through, because of the latex and the spermicide. Also I remember reading somewhere here on IG, that studies show that of the ladies that got pg. with a spermicide condom (by accident) there was a higher % of girls.
GL
Im on to our 2nd condom sway in a couple of weeks.