Is it legal if my boss sent me home today from work claiming my attire was offensive, yet other female employees had the same clothes on and were allowed to stay?

There are laws making it illegal to discriminate against employees and potential employees. For instance, you can’t be treated differently by your employer because of your age, disability, sexual orientation, gender, race, national origin or religious beliefs. If you are, that consitutes legally actionable discrimination.

That having been said, an employer is allowed to have grooming and appearance rules for its workers. And the rules can be different for different workers so long as the rules don’t discriminate on the basis of any of the above mentioned categories (gender, race, etc). Bottom line, not all employees need be treated the same; some can be given preferential treatment so long as it does not constitute discrimination under the law.

So, for example, if your employer allowed men to have tatoos but not women, that would be a case of discrimination. Why? It would be treating one gender differently than another, which is legally prohibited. If, however (and as in your case), a particular employee has been singled out because their specific tatoos have been deemed offensive in some way, then that would be legal. Why? An employer can have a rule against tattoos if they’re visible to the public if it has a reasonable belief tattoos hurt the company’s image or public relations.