So a human (Liz Shaw) and an alien (the Doctor) are about to have sex, purely out of scientific curiosity, and definitely not because they're both very, very lonely. And since their justification is that they're doing this for science--and also because it's probably just a good idea safety-wise when having sex with another species--they pause the sexytimes to run some tests. Right now I have them testing the pHs of their semen and vaginal lubrication, the normal human ranges of which were easy enough to find on the Internet, but I also want them to use a centrifuge and/or a microscope, just because I find the mental image really funny. Using searches such "semen microscope" and "semen centrifuge," Google has given me a pretty good idea of what to expect/what someone might check for in those circumstances. However, replacing 'semen' with 'vaginal lubrication' yielded nil. So:
1. What can you expect to see if you put vaginal lubricant under a microscope? What would be some things you could check for?
2. Ditto with the centrifuge.
Also, the search "pre-ejaculate ph" only led me back to the semen sites, so:
3. In typical human males, does the pH of pre-ejaculate vary from that of semen? If so, how much?
4. Are there any other tests a scientifically minded human might run on the humanoid alien they're about to have sex with?