Originally Posted by Burnt Toast
Gender (as well as the age of the donor) is not a factor. Drug testing methodologies have no ability to determine gender - they only recognize drug metabolites.
With that being stated, any human urine sample can be used as a sub as long as the donor is indeed drug-free (that includes scripted/OTC meds to avoid any hassles with the lab and/or MRO). Also, be sure that the sub donor had not consumed a large amount of fluids prior to donating the sample to you (to avoid a "too-diluted" ruling).
Employment-related U/A's are unobserved unless the donor had been suspected of tampering.