Some people feel comfortable with these methods of sexual expression and others do not. Your attitudes, beliefs, and religious convictions will help you decide what is right for you. However, a girl can become pregnant without ever having vaginal intercourse. This can happen during sexual arousal when the penis leaks semen containing thousands of sperm. Millions more spurt out the end when the male ejaculates.
Pregnancy can occur if any sperm end up on the vulva or inside the vagina.
If an egg is present in one of the fallopian tubes and is joined by a single sperm, fertilization occurs. The pre-embryo travels down the fallopian tube into the uterus. If it attaches to the lining of the uterus, implantation occurs and the pregnancy continues. The pre-embryo grows first into an embryo by the third week and then, about eight weeks after fertilization, into a fetus. During the embryonic period, the head, skeletal system, heart and digestive system begin to form.