Um, well, hazing and drinking deaths are a pretty good reason why they should be banned...
You could look into eating disorders in sororities. There's a fabulous book called Pledged by Alexandra Robbins...first link below has some info about it. And also more info:
--"Now, with 4.3 percent of Penn students reporting eating disorders, Penn has risen above the national eating average of 4.1 percent, according to the National College Health Assessment...Burnett said that she "can't get over" how many women have distorted views about eating and obsess over food and exercise. She mentioned both freshman girls and sorority sisters as being particularly susceptible to eating disorders.
"I would hypothesize that they are the most at risk," she said of sorority members. "They have already ... self-selected into this group [that has] a very heightened awareness of looks and how other people perceive them."
Then you have date rape and binge drinking:
"The "culture of drinking" on U.S. college campuses has recently gained widespread national attention. A report by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) notes the disturbing consequences of drinking on campus each year: 1,400 college student deaths from alcohol-related causes; 500,000 unintentional injuries; 600,000 assaults; and 70,000 cases of sexual assault and acquaintance rape.
Fraternities and sororities are among the key groups that foster this culture of drinking on campus...The 2001 Harvard School of Public Health College Alcohol Study (CAS), a national study of college drinking, found that fraternity members were much more likely to engage in heavy drinking than their non-fraternity peers (75.1 percent versus 48.6 percent). Among women, 62.4 percent of sorority members engaged in heavy drinking, compared with 40.9 percent of other female students...
The National College Women Sexual Victimization (NCWSV) study found that 20–25 percent of college women are victims of an attempted or completed rape during their college careers. In 9 out of 10 cases, the victims know the perpetrators. Other studies also suggest that high levels of rape take place at fraternity houses, particularly against sorority women" <<3rd link
More rape (4th link)--
Men in fraternities appear to engage in more non-physical coercion and use of drugs and alcohol as a sexual strategy than do independents.