All of the "myths" below are not true. But that doesn't stop people from repeating them or from trying to make other people believe they are true. Make sure you know what's true and what's not when it comes to sex.
If a male withdrawals (pulls out) or doesn't cum(ejaculate) during sexual intercourse, a female can't get pregnant. FALSE!
This is called the withdrawal method of birth control, but it is not an effective method of birth control) for two main reasons:
The male may not pull out before he ejaculates.
If a male has recently ejaculated (past few hours) there may still be leftover sperm in the urethra. The sperm will be released with the drops of fluid that comes out of the penis before ejaculation (pre-cum).
If a girl has sex during her period she can't get pregnant. FALSE!
There is less risk of pregnancy but because an egg may still be in the Fallopian tubes, there is no guarantee that pregnancy will not happen.
You can't get pregnant the first time you have sex. FALSE!
Wishful thinking! This is also untrue as is the myth that it takes some time before the girl's egg is willing to be fertilized by semen.
You can't get pregnant if you do it upside down. FALSE!
This must have taken some imagination. Of course it's not true. Semen are very vigorous "swimmers".
Drinking lots of Mountain Dew reduces your sperm count and the girl won't get pregnant. FALSE!
Whoever thought this up must have been taking a chemistry course. And they probably failed. This myth has something to do with the idea that certain food colouring dyes like the yellow colouring used in Mountain Dew can neutralize the sperm. Again - it's not true.
Two condoms are better than one. FALSE!
This is simply bad advice. Using two condoms will increase the friction between them and may cause both to break.
If you take someone else's birth control pills just before having sex you won't get pregnant. FALSE!
Again, this is bad advice and just not true. A female needs to take birth control pills for a full month before they become effective. Second, you may be allergic to the pills you get from someone else. Taking any prescription medication intended for someone else is dangerous.
If females douche or go to the bathroom after sex, they cut down the chance of getting pregnant. FALSE!
Going to the bathroom is something that happens in your urethra and has noeffect on sperm that is in the vagina.
You can't get pregnant if you have sex in a shower, bath or pool. FALSE!
Having intercourse in a watery environment does not protect against pregnancy or sexually transmitted infections. It's also not a good idea to have sex in a bathtub or pool because intercourse will force bath water into your vagina and may cause an infection.
If the male masturbates before you have intercourse, you can't get pregnant because the sperm are weakened. FALSE!
Pregnancy is more likely to occur after the male has masturbated. If a male has recently ejaculated (past few hours) leftover sperm may still be present in the urethra and will be released in the pre-ejaculate (drops of fluid that comes out of the penis before ejaculation).
You can find more myths at http://www.sexualityandu.ca/birth-control/birth-control-myths