Their reading of biblical teachings about particular kinds of sexual activity often fails to account for the cultural setting and circumstances in which each book of the Bible was written. (religion-online.org)
Youthful and adolescent masturbation certainly is not wicked; in older persons it will very likely be harmless, in the absence of other kinds of sexual activity and as a means of relieving physical sexual tension. (religion-online.org)
It's also possible to get pregnant from other kinds of sexual activity — even if the penis doesn't ejaculate inside the vagina — but this is way less common. (plannedparenthood.org)