The boss is threatening to abuse their power if they do not have sex. An employee can sue the boss for violating the contract.

> but in cases where one party in an exchange has a lot more bargaining power, the other party often will agree to something because of fear of retribution or a threat of force.

You seem to be implying this is bad thing but it makes sense that a company (could be thousands of people) should have more bargaining power than an employee (1 person). What is the threat of force here? That is illegal. What is the retribution here if an employee chooses a different employer because the employee wants to decline testing?