You may work at a large company and have no interaction with anyone outside of your job.In this case it would be wise to keep your private life separate from your professional life.However, employers may have another opinion on the matter. What Are the Potential Pitfalls of Employee Romances?
The rationale for why I believe this can work is due to my partner in life becoming my co-worker, who later left for a similar and challenging position.
We both continue to work directly with children as well as teach at the community college level.
Two of my coworkers have warned me to be careful, as there have just been rumors of people in the past possibly having relations and the woman was always the one to be terminated.
It is indeed legal to prohibit dating between coworkers (with a few exceptions, such as in California, where courts have ruled that the state constitution provides broader privacy protection in employment matters).
So I do believe that it is appropriate to date a colleague, however be sure that you can be respectful of one another, are aware of the boundaries and have the maturity to recognize the limitations while at work. This is an interesting question and one that is often covered within agency policy.