Question

as we know that bartholin gland or greater vestibule secretes mucus which neutralises the acidic environment of vagina and seminal fluid is also responsible for providing alkaline environment to the sperms, then how most of the sperms are killed due to the acidic environment of the female reproductive tract?

Answer 1

Normally in vagina there are many bacteria which produce acid, making the environment inside acidic and hostile for pathogens. Therefore this acidity affects the Sperms too. The female body treats Sperms as pathogens trying to enter and infect, therefore first defence is killing them. I hope you get the logic. That is why Bartholin gland is required.