Is there even any reason the police would actually need a semen sample? 
Couldn’t they just compare the DNA from a blood sample with semen found on a victim? Would collection need to be witnessed (as with a drug test)? I think I remember a reference on one of the Law & Orders. With a warrent a suspect may be forced to give hair and blood samples, fingerprints, have photographs taken of their genitalia, etc.
IANAL but I think a warrant can be issued for ahem bodily fluids of various descriptions. And I am sure there are ways of going about maintaining the legitimacy of said specimen.
Presumably, if the suspect goes on the run, the police circulate Wanted posters to better facilitate recapture.
When someone’s accused of a sex crime it’s SOP to take photos of more their private regions to compare the the victim’s descriptions.
BTW are their any other ways of obtaining semen without the subject needing to masturbate or ejaculate? Forcing a subject to do either against his will seems like it be a sex crime in and of itself.
Why would an investigator want semen? Can’t they get the same information from a cheek swab?
Understandable and logical.
I did find a cite for this (Debra Lafave) but I was still surprised. I’m not sure this happens in the UK though. Hopefully someone will confirm one way or the other.
I have by no means done an exhaustive search, but I have found no indication that the accused will have to provide a semen sample as part of the legal proceedings. Samples may be collected off the victim in ways that vary state to state (and are not always pretty to talk about).
The accused may have blood drawn for DNA samples and testing for HIV or other STD’s, saliva may even be taken. I don’t really know why a semen sample would even be necessacary.
Sgt Schwartz
I’m pretty sure a swab can be and is used to get a DNA match. The DNA in semen is the same as DNA in blood/saliva (okay technically there’s only half of it but an exact match of half of someone’s DNA is statistically as significant as a full match).
That’d depend on how soon afterward the cheeks were swabbed, and what kind of rinse was used, I’d suspect.
I was going to say “it depends whose cheek gets swabbed” but yours is better.
Well, for the vast majority, yes this is true. But there is a genetic disease (I know the ‘off-hand’ term is chimera, but there has to be a better medical term,) where a person has different DNA at different spots in their body (of course, this is mostly from a Law and Order episode, so it might not be entirely like that.)
I also recall an L&O ep. where they didn’t have enough time for a full DNA match, or something, but they did notice the subjects sperm in the sample from the rape kit was unusually low, so they had their two prime subjects give a semen sample to compare their sperm counts.
Hmmm - do we have any CSI writers online who can give us the definitive answer? 
I couldn’t think of a hypo where a semen sample would be needed that a buccal swab wouldn’t be sufficient to collect DNA, so I called over to the DA’s office and asked a pal over there his opinion. His off the cuff answer was that he would expect that a judge would likely have the authority to issue such a warrant, but couldn’t think of any reason to do so either except a few hypos where the person might wish to do so voluntarily.
I don’t know, see some collection problems. I wouldn’t want to be the deputy serving that search warrant!
So the government can order a person to masturbate against their will :eek: ? I’d love to see a defence attorney’s challenge to that warrent!
Like I said, I can see some collection and enforcement problems. I have no idea how you’d go about taking a semen sample from an unwilling donor…maybe test his shower grate. At any rate, neither of us could think of a reason why it would be necessary.
We have an interesting case here in Texas where a judge has issued a warrant to have a bullet lodged in a teenager’s forehead out so they can test the ballistics and see if he was involved in an attempted murder. The warrant is being challenged and it’s unlikely that the state will be able to find surgeons willing to do it even if the warrant is ruled valid.
And in the end it was true - alphaboi867 really did love Big Brother…
“Somehow,” this guy got another inmate’s blood, semen or saliva into his mouth to try to beat the DNA test.
From a Canadian legal perspective (human rights jurisprudence is not too different from the US) you would definitely have a hard time getting such a sample authorized. Courts have always been reticent about forcing someone to do anything to their bodies (even blood samples were refused outside of the gravest circumstances) because it is a violation of the person. The general view is that 1 - specimens should only be taken from a person if absolutely necessary and 2- such sample should violate the person’s rights in the least possible way.
Thus, for a sperm sample, there would have to be a VERY good reason (i.e. necessary to prove a rape or murder) and that the same information could not be obtained by a simple DNA test.
I’d like to know what happens if the person refuses.
Taste test?
I’m going to hell