It may come as a surprise to some grad students and postdocs to find that the NIH strictly prohibits
labor obtained by any of the following methods: the recruitment, harboring, transportation, provision, or obtaining of a person for labor or services, through the use of force, fraud, or coercion for the purpose of subjection to involuntary servitude, peonage, debt bondage, or slavery.
It also appears to be the case that if you are a private grant awardee (as in a company awarded an SBIR I guess?) or are on-the-job for a public grant awardee you may not:
ii. Procure a commercial sex act during the period of time that the award is in effect;