...a guy doesn't ejaculate during sexual intercourse and/or pulls out of my vagina before he ejaculates?
Yes, it is possible. A small amount of fluid that contains sperm comes out of the penis long before a guy ejaculates. It can also be difficult for guys to control when they ejaculate, so they may not be able to pull out before ejaculating.

 ...a girl has sex during her period?
While there is less risk of pregnancy, it is still possible. Because an egg may still be in the Fallopian tubes, there is no guarantee that pregnancy will not happen.

 ...you're having sex for the first time?
Yes. Anytime a girl has sex with a guy, there is a chance she may become pregnant.  It does not matter if it's your first time or your last time. It is even possible for a girl who has never had her period to get pregnant because anytime an egg leaves the ovaries, it is ready to be fertilized.  Therefore, if a girl has sex around the first time she ovulates, it is possible that her egg could be fertilized and she could get pregnant.

 ...you have sex upside down?
Yes. There is no sex position that will prevent a girl from becoming pregnant.  Sperm are designed to find the egg and they stay alive for about 2 full days inside a girl's body to try and do so.  Once sperm are inside a girl's reproductive system, there is a chance she can become pregnant - no matter what position she was in when they got there.

 ...the guy drinks lots of Mountain Dew?
Yes. It is a myth that Mountain Dew reduces a guy's sperm count - it is completely untrue. Mountain Dew, or the food colouring dye in Mountain Dew, doesn't neutralize sperm and cannot prevent a girl from getting pregnant.

...we use two condoms instead of one?
Possibly. It is bad idea to try and use two condoms instead of one. Using two condoms will increase the friction between them and may cause both to break.  If you want to use extra protection to make sure you don't get pregnant, you can use lubricant to prevent the condom from breaking, or girls can consider taking prescription birth control medication or another form of contraceptive.

 ...if I take someone else's birth control pills just before having sex?
Yes, it is possible. A girl 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 I wash my vagina or go to the bathroom (pee) after sex?
Yes, it is possible. Washing your vagina after sex can actually increase the risk of getting pregnant. The fluid could force semen into the uterus where it could reach the egg in the Fallopian tubes and fertilize it.  Going to the bathroom and peeing has no effect because urine does not go through the same parts of your body as sperm.  Once sperm are inside a girl's reproductive system, there is no way of getting them out.

 ...if we have sex in a shower, bath or pool?
Yes. If a guy ejaculates inside a girl's vagina in a shower, bath or pool, there is the same chance she will become pregnant as having sex anywhere else.  However, if a guy ejaculates into a pool, hot tub or bath he is sharing with a girl, the sperm will not be able to swim through the water to the girl.

 It's not a good idea to have sex in a bathtub or pool because intercourse will force bath water into your vagina and could cause infection. In any case, the water will not have any effect on whether or not you get pregnant.
 
...if my partner masturbates before we have intercourse?
Yes. While it is possible the guy may ejaculate fewer sperm, your chances do not change a whole lot when there is only 200 million sperm instead of 500 million. Each of those sperm have the same "strength" and have the same purpose, which is to find an egg. Sperm stay alive for up to 2 days, which gives them lots of time to find the egg.

...if we have anal sex?
There is a chance. If any sperm leaks from the anus, it is possible that it could enter the vagina and pregnancy could occur. Anal sex is therefore not the best way to avoid becoming pregnant. It is better to use regular contraception such as condoms and/or another form of birth control.

 ...if we have oral sex and I swallow his sperm?
No. A woman cannot become pregnant from giving oral sex, even if she swallows his sperm. A woman can only become pregnant if sperm get inside of her vagina.

 ...if my partner ejaculates on my pants? Can sperm pass through clothing?
No, generally clothing acts as a barrier against sperm.

Make sure you know what's true and what's not when it comes to sex. There are many myths out there about ways that a girl can or cannot become pregnant. There are also many people out there who will repeat these myths and try to make other people believe they are true. Before performing any sexual activity, people should respect themselves enough to find out the truth so they know how to best protect themselves.