There are better ways to prove guilt then making a teenager go to the hospital, get an injection, and have pictures taken of his erect penis. I am just calling for a humane and just way of gathering evidence. This could cause years of emotional damage for someoine who has yet to be convicted.

An article related 

http://www.washingtonpost.com/blogs/local/wp/2014/07/09/in-sexting-case-manassas-city-police-want-to-photograph-teen-in-sexually-explicit-manner-lawyers-say/?tid=sm_fb