Warning: despite the facts I am going to present, and they are facts, this is not an endorsement for carelessness. Use proper birth control methods every single time.
My regular readers will no doubt know by now that exposing myths about sex and birth control is a theme of mine. In the past I have explored dangerous or foolish myths that I was doing a service in proving false. There are some myths about birth control however that take a shortcut to the desired result by fudging the reality a little or exaggerate the truth and they do a service by this, because the truth would be abused as reason to be careless. I value the absolute truth over the effect of these myths, but in exposing them I am trusting my readers to consider every last word I have to say. Taking the following explanations out of context could lead to a disastrous misunderstanding. Read every word of the explanation and not just the heading.
Myth #1: pre ejaculate contains semen
This is a case of the lie being a quicker route to the overall truth then carefully explaining the truth. I would like to stress that you should act as if pre ejaculate does contain viable semen, even though it does not. The reality is that pre ejaculate comes from the bulbul urethral gland while semen enters the urethra through the seminal vesicle. pre ejaculate is pure mucus, serving the purpose of clearing away urine and lubricating the urethra so semen can pass through safely. It can carry residual sperm cells laying in the urethra out with it, though any such sperm laying in the urethra are likely to have been dissolved by urine before this could happen, though there are parts of the urethra free of contact with urine where sperm cells could reside. The reason it is better to believe it does contain semen is because you can't tell the difference. By this I mean the man could ejaculate a little bit, several times in fact, and this absolutely does contain semen. DO NOT trust yourself to tell the difference. Even if you could tell the difference, and you absolutely cannot, the possibility of residual semen being carried out with the pre ejaculate exists.
Myth # 2: pulling out doesn't work
Before I explain this one I would like to emphasize that I say the following for the sake of entertainment and not for the sake of argument. Though it is absolutely true, this is not a defense of this as a method of birth control. Use an actual method of birth control. That said, you may find it surprising to know that performing coitus interuptus as it is officially known correctly can be 96 percent effective. By correctly however I don't mean pulling it out as the orgasm begins (which is 81 percent effective at best) I mean having the discipline to not ejaculate at all. This isn't 100 percent because obviously the man could ejaculate a little and not know, or his pre ejaculate could carry out residual sperm as explained above. These aren't odds worth playing as your sole method of birth control. I mention this as a myth only to explain that it is not the spectacular failure of a method that it is known as.
Myth # 3: it only takes one sperm to cause a pregnancy
This is usually offered as an exaggeration, the purpose of which is to convey the true meaning: don't be careless, it's easy to cause a pregnancy. That is actually sound advice. If you do nothing in the way of birth control, you are 86 percent likely to cause a pregnancy with each incident of intercourse. The truth of this is that technically it takes several sperm cells to penetrate an ovum. A single sperm or a few wouldn't do the job. The reason this truth isn't worth knowing however is that there is no time in which you will be dealing with such a thing as one or a few sperm. They come in millions and a lone sperm is not going to force its way through a microscopic pore in your condom and make its way to the uterus, which brings us to our next myth.
Myth # 4: condoms are not entirely reliable
I don't know if any of you have heard this before but it's out there. To be fair, this one depends on your idea of entirely reliable. If by this you mean infallibly works every time then no, they aren't entirely reliable. They can fail 3 percent of the time, which seems to be a scary amount of failure possibility. It's important to understand that this does not mean 3 out of every 100 times you have sex using a condom you are going to conceive a child. It means that every single time you have a 3 in 100 chance of conceiving a child and this does not increase each time. It could happen the first time and it could happen never. In realistic practice, if you regularly have intercourse (regularly meaning almost every day) and use a condom you will most likely have one failure per thirty years. This is why you should use multiple methods such as the pill and condoms in conjunction. This failure percentage is not the end of the matter, and the most important thing to understand about condom failure is HOW they fail. It is not, as I have heard some people think, that some sperm cells get through the pores in an intact condom. They are designed correctly so that this does not happen. Condoms fail when they break or fall off. To prevent this you can take certain measures such as making sure they are not expired, squeezing the tip before putting it on so that it does not gather air pressure, rolling it all the way down the length of the penis so it won't fall off during intercourse, stopping and putting on a new one if you are uncertain or if you have been engaging in intercourse for much more than ten minutes or so. If it does break or fall off the best thing, for the female, to do at that point is to go immediately to a pharmacy and pick up an emergency contraceptive (you do not need a prescription) and take it as soon as possible. This is not an effective measure all on its own; it is an emergency measure but an effective one. You are statistically unlikely to ever have an unwanted pregnancy if you follow these guidelines.