[bkeroack]

It's not a "[m]en and women need to learn to interact at work" issue. It's not your job to teach employees this. It's a business continuity issue. If an employee is kept on who shows this kind of totally inappropriate behavior it can become an existential threat to the company.

If (probably "when") the behavior continues--or worsens--now you're responsible for keeping an employee that has a known history of sexual harassment. I would posit that there is not a single employee so valuable as to be worth this risk.

[vacri]

Speaking of business continuity, staff churn is costly and time consuming - advertising the position, doing interviews, negotiating, paying a recruiter... and even when you finally get the new employee, it takes a few months before they're fully familiar with the job.

It's worth having a talk first to try and fix things, warning the employee that it won't be tolerated again. It's not like once you have the talk you lose all future opportunity to fire them.