I have no idea, but perhaps it would be a good idea to stop walking around with semen dribbling out of some orifice or other.
It just occurred to me - are the floorboards uncoated?
I am shocked that a sincere question about semen stains posted on a public message board would elicit anything other than serious replies.
Shocked, I say.
Sarcasm? I see what you did there!
Thanks to all for the serious suggestions. I’ll give them a try. If any actually work, I’ll post the background story.
You might have something if the OP started with "there are about six** [to nine]** tiny white ‘circles’ where semen droplets landed. "
You could also try taking a piece of walnut (the part you’d eat, not the wood) and rubbing it on the spots. That’d stain them back to something closer to the original color.
For some reason rubbing nuts on the floor doesn’t strike me as the best answer.
I think we have a winner! 
I third Nature’s Miracle. This version says it is safe for sealed wood floors.
Have you actually used this product (even if not for OP?)
No, that was a serious answer. I’ve seen walnuts used for covering scratches in wooden furniture, and wouldn’t have believed how well they worked until I saw it.
Discolourations on hardwood floors are not the easiest things to fix. Wood usually darkens as it ages, if you simply sand down a spot and reseal it, you will end up with a very visible spot even if you use the same stain and sealer. Are the stains that obvious? Hardwood floors are a rustic product, they get dents, scratches, discolourations from carpets and furniture. Is it really that big a deal? Because the fix can be a pretty big deal.
Is this an old floor or a modern polyurethane coated floor? Is the stain the top coat? If not how did it penetrate the sealer to get into the wood? If this an old waxed floor, first try polishing it with some wood floor wax. If polyurethane you can try a touch up with some varathane - beware, there is oil based and water based, satin, semi-gloss, and gloss, all giving different results. You may have to buff out the stain before refinishing.
Semen is not exactly battery acid, it should not stain most wood finishes. Some old wood floors were shellac and become cloudy with water damage. I would guess that you would buff out the affected area and apply a fresh coat of shellac, but I have never worked with it as a wood finish.
Well, it’s not obvious that it’s semen. It’s just six white (perfectly circular) spots scattered across two rooms. It’s not a huge deal. I just wish I could get rid of it.
It’s definitely a modern coating: probably polyurethane. If fixing it requires any kind of ‘home improvement’ project beyond buying a simple cleaning solution, I’m not even going to bother.
Looks similar to this:
http://i.ehow.co.uk/images/a04/l4/13/clean-polyurethane-wood-floors-200X200.jpg
Yeah, that’s probably what caused the problem in the first place.
mmm
Try using a mr clean magic eraser. Not only does it work on floors, it works on walls and ceilings too. (don’t ask.)
I don’t even want to know how you ended up at this nearly two year old thread.
Don’t ask? You know that the magic eraser can get semen out of the ceiling and you expect people to not ask?
zombie or no
i’ve thought that the best way to clean coffee stains in a cup is with fresh coffee. maybe similar.