with the constant progression of testing protocols it may not be wise to use the urine of the opposite gender.
Testing protocols have not progressed to the point where a person facing an employment-related U/A is subjected to genetic profiling. Labs practicing in the US are still prohibited from conducting any form of genetic testing on urine samples collected for an employment-related U/A. Such donors are protected from genetic profiling under the Genetic Information Nondiscrimination Act (GINA) of 2008.

With that being pointed out, any human sample can be used as a sub as long as the sub donor is known to be drug-free and not overhydrated prior to donating the sample. Donor gender and age is NOT a factor.
Urine luck... I have used this synthetic for many years and I must say that it is the best out there IMHO.
As I had informed you in another post, the correct name is Quick Fix for the synthetic urine - not "Urineluck". Urineluck is the drop-in additive used to spike a dirty urine sample.
http://boards.cannabis.com/drug-test...ashington.html