Bengtson and ruhlen have complied a list of 27 etymologies that are found world-wide. One of them is "dirty":
21. *PUTI—'vulva' —— English slang poontang < French putaine 'whore' < Vulgar Latin putta 'girl' < Proto-Indo-European *puto 'cunnus' > Sanskrit putau 'buttocks', Nepali puti 'vulva' Old Icelandic fuð 'cunnus', Middle High German vut 'vulva';
Malinke butu 'vulva';
Songhai buti 'vulva';
Proto-Afro-Asiatic *pwt 'hole, anus, vulva', Hebrew pot 'vulva' ("secret parts" in the King James Version, Isaiah 3:17), Somali futo 'anus', Oromo fudji 'vulva';
Tamil puNTai 'vulva', poccu 'vulva, anus';
Malayalam pûru 'buttocks, vulva';
Kannada pucci 'vulva'; Telugu pûDa 'anus'; Tulu pûTi 'vulva';
Middle Mongolian hütü-gün 'vulva';
Old Japanese photo 'vulva' (mod. hoto);
Proto-Eskimo-Aleut *putu 'hole';
Proto-Caucasian *put‘i '(female) genitals'; Svan put‘u 'hole';
Basque poto-rro 'pubis, vulva';
Australian Aboriginal Luridya puda 'vulva';
Maori puta, Tagalog puki 'vulva';
Delaware saputti 'anus'; Mohegan sebud 'vagina'; Chinook puch 'penis'; Quechua upiti 'anus', Aymara phuthu 'hole'