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Whether you are male or female, you should educate yourself about pregnancy before any heterosexual activity. Here are a few basics that all sexually active people should know about pregnancy:  Pregnancy can occur anytime that semen enters the vagina. Almost all pregnancies result from unprotected penetrative sex, with the penis in the vagina. Pregnancy is extremely unlikely during oral sex, anal sex, or non-penetrative sexual activities.  Precum (a fluid the penis releases in small amounts when aroused) typically does not contain viable sperm. Unlike semen, precum is unlikely to cause pregnancy. All types of unprotected vaginal, oral, and anal sex can spread sexually transmitted diseases (STDs). You can only get an STD by sharing fluids with someone already infected. However, many people have an STD that does not cause visible symptoms, and this can still be transferred during sex and cause major health problems (such as female infertility). The Center for Disease Control recommends annual STD testing for sexually active women under 25, and for men who have sex with men. Men who do not have sex with men are at lower risk, but should still be tested after risky sexual behavior.  Some STDs can take six months or longer to show up on a test. If you and your sexual partner only have sex with each other, you only need to be tested once. Get tested again if you suspect your partner has had sex with someone else, or if either of you have used injected drugs with a shared needle. Condoms are the most common method of birth control among teens. They are cheap, easy to use, and protect you from both pregnancy and sexually transmitted diseases. Make sure you are using them correctly. Male condoms reduce pregnancy chance to 2% per year when used perfectly, but during typical use, mistakes or lapses increases this to 18%.  Female condoms are slightly less effective, reducing the chance to 5% when used correctly. Do not use a female and male condom at the same time.  Using condoms and one of the methods below is an excellent way to protect yourself and your sexual partner. Birth control pills are very effective at preventing pregnancy when a woman takes one every day. They do not protect against STDs. "The pill" is available over the counter in many countries. In the U.S., you need a doctor's prescription.  U.S. law prevents your doctor from telling your parents about your birth control. However, they may find out if you pay for it using your parent's health insurance. Birth control typically costs $15–$50 per month, so you and your sexual partner may be able to pay for it yourselves.  These pills are very safe for most women, but may cause health issues if you have serious health issues related to your heart or blood. Smoking increases this risk. Birth control pills make your menstrual cycle more regular and may reduce unpleasant side effects, such as acne and cramping. Women are most fertile during ovulation and for a few days afterward. This usually happens on days 11–21 of a 28-day menstrual cycle, where day 1 is the start of menstrual flow. It's important to realize that most women do not have regular cycles, so you can't predict exactly when this happens in advance. This tells you when pregnancy is especially risky, but you shouldn't skip protection at other times of the month.  Sperm can survive for a few days in the vagina, so sex before ovulation can still lead to pregnancy. To track this, keep a menstrual cycle calendar with signs of an approaching period. If you want to be extra safe, track your ovulation. There are many other forms of birth control available, from diaphragms to intrauterine devices. For more information, visit a reproductive health center such as Planned Parenthood, or talk to a doctor or gynecologist. Teens are exposed to many myths about birth control and STDs, so don't assume everything you've heard is true. The withdrawal method, where the man pulls out before ejaculation, is not recommended by most experts. While it does reduce pregnancy somewhat when followed correctly, there is a risk the man will not pull out in time, or change his mind after sex has started. This method also offers no protection against STDs.
Understand pregnancy. Learn about sexually transmitted diseases. Use condoms. Consider birth control pills. Track the fertility cycle. Research other forms of birth control.