Some sexual protections could be extended to slaves. The conduct of slaves reflected generally on the respectability of the household, and the "materfamilias" in particular was judged by her female slaves' sexual behavior, which was expected to be moral or at least discreet. This decorum may have limited the exploitation of female slaves that were part of the "familia". Seneca expressed Stoic indignation that a male slave should be groomed effeminately and used sexually, because a slave's human dignity should not be debased. The burgeoning trade in eunuch slaves during the early Empire prompted legislation under the emperor Hadrian that prohibited the castration of a slave against his will "for lust or gain". Legal agreements on the sale of a slave might include a "ne serva prostituatur" covenant that prohibited the employment of the slave as a prostitute. Although concern for the slave's welfare may have been a factor in individual cases, this legal restriction seems also to have been intended to shield the male citizen owner from the shame or "infamia" associated with pimping and prostitution. The "ne serva" covenant remained in force for subsequent sales, even if the buyer was initially unaware of it, and if it was violated, the illegally prostituted slave was granted freedom.