When a woman has sex without a condom, she acquires, as her private property, semen. It is in her body, and (as we all know) a woman controls her own body and what's in it. Sperm-banks sell semen, so semen also has economic value (admittedly the value is greater if it comes from a racehorse). So women, as a result of having sex with a man, receive a GIFT--property with a fair market value--and should have to report that on their tax returns.
I suspect few do. It could be history's greatest fraud. What is the value of one standard unit of human semen ("wad")? I'm just guessing, but say it's $50. If you imagine how many wads have been received by women lately, you get a juicy picture. The potential revenue is huge. This could be a way to fund our schools. We might start by collecting an estimate of the back-taxes; in the future, we should assume that all women receive a certain standardized amount of annual semen unless they prove otherwise--just like we do with waiters and tips. Semen tax would be "progressive," since it would encourage abstinence (or at least safe sex) and so promote public health and family values, while funding needed social programs.
I urge concerned citizens to get behind this idea next election, instead of that dumb sales tax idea. How can you tax an activity that COSTS MONEY IN THE FIRST PLACE, like buying stuff, when there's another activity going on all the time that transfers a valuable asset to people?! Is not the latter the definition of income? And do we not tax income? At the very least, it's a gift tax. People, wake up! OUR CHILDREN'S FUTURE DEPENDS ON IT.