Say a “snipped” man raped a woman.
Apart from any other evidence left at the scene and barring witness testimony, would the police know anything about the man (genetically) by what fluid he does ejaculate?
Yes, there are seminal fluids which are ejaculated aside from sperm. These fluids do contain the DNA necessary for identification.
Assuming the man in question is a “secretor”. Not all men secrete identifiable DNA in seminal fluid.
Don’t forget the possibility of hair and skin evidence left behind.
Here’s Cecil’s column on this topic.
Oops, I mean a mailbag article. Still, there it is.
seminal fluid secreted from the prostate gland still has identifiable DNA in it. during a vasectomy, the Vas Deferens are cut before the prostate, so the seminal fluid is secreted as per normal. The DNA in the actual sperm itself is specific for that of reproduction ie: only contains half the amount of chromosomes as normal DNA.
so in theory, yep, you could be ID’d from it. and as SEWALK mentioned, the other hair and skin evidence left behind! You’d be amazed at what forensics can pick up now. Even the tiniest skin flake left on a jumper can be enough to ping the crime on someone!