It's well documented that the Duggars have a lot of strict views when it comes to marriage and sex. The family-of-21 considers themselves followers of Christ and the Bible, though their exact religion has never been revealed.
Jim Bob and Michelle Duggar enforce a lot of rules on their kids, especially the girls, regarding how to act when courting. For example, none of the kids are allowed to have social media accounts until they're engaged. They also are not allowed any physical contact with their partners, including hand-holding, until they're married.
Another interesting rule the Duggar girls are expected to follow is "be available," as in be ready for sex whenever your husband wants sex. Michelle advises her daughters to have sex with their husbands whenever he wants, regardless of if THEY want to. The only time you're allowed to say no is on your period, and a slight break after childbirth.
"Be available," the Duggar matriarch tells Today. "Anyone can fix him lunch, but only one person can meet that physical need of love that he has, and you always need to be available when he calls."
Of course, sex is seen as a sacred act for the family so birth control is also out of the question, as they believe the point of sex is procreation. That would also explain why they do not believe in premarital sex, which frankly isn't an uncommon point of view. However, some of the Duggar sisters have a more extreme opinion on why you should't have premarital sex.
It'll kill you.