U.S. Women's Soccer Star Alex Morgan -- FIFA Is Treating Women Like Second Class Citizens

U.S. women's soccer star Alex Morgan says FIFA is using women as "guinea pigs" by making them play their World Cup on artificial turf while the men have no plans to switch any time soon.

Morgan and several other women's soccer players are furious the 2015 World Cup in Canada will be played on artificial turf as a "test" … while the men will play on grass for their next two World Cups.

She tells TMZ Sports, "They are treating us as second class to the men ... Using the women as guinea pigs in their experiment is just not right."

Morgan says she understands certain venues have limited resources, but when it comes to the World Cup ... there should be no settling. Especially because artificial turf increases the risk of injury, and -- many believe -- decreases the quality of play.

There are no plans to boycott, but Morgan helped organize a group of more than 40 players that has hired a law firm to request FIFA reconsider the use of turf.