Sexual orientation discrimination involves treating an employee differently solely because of his or her sexual orientation, generally this means on the basis of whether they are homosexual, heterosexual or bisexual. 

There is increasing support for expanding legal protections in this area.  Laws prohibit discrimination against individuals based on sexual orientation, or perceived sexual orientation.  Many of them are now covering the private employment context: including but not limited to recruitment, hiring, firing, promotions, benefits, compensation, job training, job assignments, and other terms, conditions and privileges of employment.

It is not relevant whether your employers correctly understood you to be gay, lesbian, or bisexual or transgender. If your employer believes or perceives you as having a certain sexual orientation, and treats you differently or discriminates against you because of it, then it is highly likely they are in violation of the law. If you have noticed such disparate treatment in conjunction with work, then you might wish to contact an attorney who focusses on employment and discrimination laws.