I admit it. I am a Trekkie. I have always loved Star Trek with all the science fiction it oozed in every episode. However, I am probably not a true Trekkie relative to most of the Trekkies out there, but relative to the rest of the public I am a Trekkie nonetheless. A gray zone Trekkie, if you will. But that is besides the point. This is simply to explain why I have thought of this current posting, since in retrospect it is an odd thought.
One of the basic tenets of science fiction is that of space travel. And with space travel comes many special problems, such as the aging space traveler, time travel, and black holes. The one constant in all these scenarios is the speed of light. The laws of physics tell us that nothing can go faster than the speed of light in a vacuum. (I say vacuum because you can slow light down in certain substances.) And because light at comprised of photons can have different spins (like electrons), light carries information. The corollary then is that information cannot travel faster than the speed of light. Information in the most basic sense being on/off or 1/0 or yes/no. You can also split a photon into a pair of photons with a laser. This results in two photons that are entangled, or joined in their quantum properties. Since photons have spin, the entangled photons will have opposite spins. When the photon is initially split into entangled photons, there is no way of knowing which way either resultant photon is spinning. You only know that they are spinning in opposite directions. But if you were to measure the spin of one of these entangled photons, its counterpart would instantaneously adopt the opposite spin of the photon whose spin you just measured. And it does not matter where the photons are in relation to one another because there are entangled in a quantum sense. So if they were ten feet apart, checking the spin of one photon instantly decides the spin of its entangled pair ten feet away. If they were a light year apart, the same instantaneous effect would occur. By that logic, you could imagine how information could be transmitted faster than the speed of light.
What if this was true for finding out the sex of a baby? For the first four months you have no idea the sex of the baby. But then comes the day when you can find out the sex if you want. Up to that point, it could be a boy or a girl. We like to believe that the sex is already determined because the chromosomes decided that at the time of conception. But there really is no way of proving that theory no matter how much logical and scientific sense it makes. It is just as likely for there to be an alternate universe with a "quantum" paired pregnant female or a "quantum" paired pregnant female on the other side of the Earth or across town, and finding out the sex of one baby determines the sex of the paired baby. This would a corollary to the theory that everyone has an evil twin somewhere. But then the problem is that you'll never know if you are the one "determining" the sex of the baby or simply finding out the sex because your paired pregnant counterpart has already "determined" the sex of her baby.
You would have to somehow find your paired pregnant counterpart first...