An interesting report claims that 1 in 3 employees are afraid to come "out of the closet" due to harassment fears from other employees and management. I have experienced this in several work environments, including jobs in what is considered one of the most liberal cities in America, Las Vegas, NV.
As stated in this report by Andrew Harmon from The Advocate:
An alarming percentage of gay individuals face employment harassment and often decide not to disclose their sexual orientation in the workplace, according to a summary of recent social science data by the Williams Institute.
In a review of studies including the 2008 General Social Survey, a national probability survey, the Williams Institute reported Monday that 38% of lesbian, gay, and bisexual employees who are out at work reported being harassed because of their sexual orientation. More than one-third of respondents said they were not out to any colleagues at work.