I would like to know if shallow penetration can get one pregnant, or does only deep penetration make one pregnant?
No, the penis does not have to penetrate far to result in pregnancy. There have been cases where pregnancies resulted with no penetration at all. All that needs to happen is sperm must get to the ovum (egg). Simply spilling fertile semen on the vulva can be enough to allow sperm to enter the woman's body. Once the sperm get inside, they can make their way up through the uterus and Fallopian tubes toward the ovum, and thus conception!
Therefore, if you intend to prevent pregnancy, the male needs to keep his penis covered with a condom during ALL genital contact. Pre-ejaculatory fluid can contain sperm, too, so it is important to keep all sexual fluids from exchanging during sexual play.
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