Stoke defender Robert Huth has been charged by the Football Association over interactions on Twitter.
Huth, 30, replied 12 times to an account that asks users to guess the gender of individuals pictured in explicit images.
The FA contests that Huth's replies "were indecent and/or improper and/or brought the game into disrepute".
It adds that they were an "aggravated breach" of the misconduct rules, as the German made reference to gender.
Huth has until 18:00 GMT on 21 January to accept or appeal against the charge.
If he is found guilty, the FA regulatory commission is free to impose any sanction it feels appropriate.
There is a minimum five-match ban for players who make disparaging reference to people's race, gender, religion or sexual orientation on the pitch.
Centre-back Huth deleted his messages and wrote: "Clearly no offence was meant or directed to anyone but apologies if I've offended anyone."
Stoke declined to comment.
Former Chelsea and Middlesbrough player Huth has suffered a succession of injuries this season and has only featured in three matches for his club.