If you take off a condom and put a new one on what are the chances that she will get pregnant?
I must assume that since you are concerned about pregnancy that you are engaging in sex with a woman to whom you are not married. Regardless of the odds of pregnancy occurring, the odds that you are committing sins that will lead to your condemnation is high. The two of you are guilty of fornication. "Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived. Neither fornicators, nor idolaters, nor adulterers, nor homosexuals, nor sodomites, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners will inherit the kingdom of God" (I Corinthians 6:9-10). It doesn't have to end this way, but to change the outcome, you must change your behavior. Sex only belongs in marriage. "Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge" (Hebrews 13:4). I would like you to read "Why Sex Outside of Marriage is Wrong" because I am concerned that your soul is in danger.
When 100 married couples regularly engage in sex, 85 of them will find that they have conceived a child in one year if no contraceptive is used. When a couple uses condoms, the number of conceived children drops to 19 out of the hundred. There are a number of reasons why the number isn't zero. Condoms do fail. The United States requires that no more than 7% of sampled condoms fail when tested. To put that in perspective, how would you like to eat at a restaurant where no more than 7% of the diners get food poisoning? Also, users of condoms do make mistakes at times putting them on, which increases the possibility of failure. And there are times when the condom slips or rolls up allowing semen to escape. Also, since a condom can only be placed on an erect penis, there are high odds that pre-ejaculate fluids will come in contact with the vagina. Even pre-ejaculate fluid can contain some sperm. And finally even the most regular condom user sometimes wonders what sex is like without a condom, or a condom is not conveniently available and figures it won't hurt just this once.
Replacing a used condom doesn't directly increase the odds, but since semen has been released, it is possible to get some on your fingers or on the body end of your penis. Since condoms do not completely cover the full length of the penis there is a very remote chance that some sperm will be on the outside of the condom and come in contact with the vagina. Sperm swim, so they don't have to be placed deep in the vagina to get a woman pregnant. The odds are low that an accidentally placed sperm will reach an egg, but the odds are greater than zero.
What isn't often discussed and should be of greater concern is that condoms don't completely block the spread of sexually transmitted diseases. The primary reason is that a condom doesn't cover the entire length of the penis, leaving an area for skin-to-skin contact. Also, since condoms can't be put on until the penis is erect, there is usually contact between the genital areas without any barrier. Finally, some sexually transmitted diseases are slowed down by a condom, but some are so small that they can pass through the latex barrier.
"Drink water from your own cistern, and running water from your own well. Should your fountains be dispersed abroad, streams of water in the streets? Let them be only your own, and not for strangers with you. Let your fountain be blessed, and rejoice with the wife of your youth. As a loving deer and a graceful doe, let her breasts satisfy you at all times; and always be enraptured with her love. For why should you, my son, be enraptured by an immoral woman, and be embraced in the arms of a seductress?" (Proverbs 5:15-20).
No, I am not married to her. I am 15 years old. Your information has been very helpful and I thank you greatly for it.
I would be happier to know that you've decided to wait until marriage before having sex again. I hate seeing young people mess up their lives over a temporary pleasure that has such long-lasting effects.