A video posted online has shown the horrific extent of sexist abuse channeled towards female Chelsea team doctor Eva Carneiro.
Manchester United fans are heard chanting "get your tits out for the lads" as she walks along the touchline at Old Trafford, with one other fan shouting "show us where you piss from you slag, show us your minge".
This video surfaced after another incident showed Arsenal fans shouting "have you ever had a Gooner up your arse?" at a separate match.
The incidents have prompted the Football Association to ask fans to report any sexist abuse they witness at football matches.
Heather Rabbatts, chair of the FA Inclusion & Advisory Board, said: "Dealing with sexism in football is something which needs to be tackled by all in the game.
"We need to respond to the issue with a range of methods, from guidance to stewards to the continued encouraging of reporting. Kick It Out has an app, the FA have a range of short films which guide both players and fans through the process, for swift and effective reporting of all forms of discrimination."
Laura Bates, founder of the Everyday Sexism project, said: "We have received numerous entries from people who have experienced sexism, harassment or abuse whilst playing, watching, supporting or working in football.
"It is time that clubs and fans alike stand together and take responsibility for creating a space where everybody can enjoy football, free from any kind of prejudice".
Chelsea FC, who have employed Carneiro since 2009, said: "The issue of equality is one we take extremely seriously and we abhor discrimination in all its forms, including sexism.
"Such behaviour is unacceptable and we want it eradicated from the game."
The incident was reported to the police by Manchester United.
A Women In Football survey found last year that two-thirds of women working in football had experienced some kind of sexism or harassment and 89% had witnessed it but not reported it.