Meanwhile, shallow penetration is supposed to boost your chances of having a girl, because according to Shettles X-carrying sperm are more robust, and therefore survive longer in the harsh vaginal environment. (newscientist.com)
[2] These organisms maintain an acidic vaginal environment with a pH of 4 to 4.5. (chiro.org)
Cervical fluid is more alkaline than the slightly acid vaginal environment. (natural-fertility-info.com)