Sibling incest is not young similarly aged siblings curiously looking at each others genitals. It is initiated by one sibling, and there is usually a 3 (or more) year age gap. Risk factors for sibling incest include power imbalances, parentalized siblings, lack of sex education, and other forms of abuse already occurring in the home. Judging by the general information we have about the Duggars, a lot of these factors are present. The sheer amount of children dictates that the older children care for the younger ones. And in the police report interviews, none of the children interviewed even knew the correct names for the human anatomy when it came to genitals.
In a large homeschooling family, older siblings are often in charge of the younger ones. Younger children are expected to obey their older siblings as they would a parent, and may face punishment from the parents or even the siblings if they do not obey. This creates a hierarchy where the younger children are basically powerless, and have already come to expect that they do not have a say in how they are treated. Sexual actions initiated by the older sibling are not likely to be resisted or talked about in this sort of relationship.
If a parent is physically or emotionally largely unavailable such as would be the case for anyone with 19 children, parenting younger children can often fall to the older ones.The older child is often experiencing the parental neglect as well, and since they are not emotionally mature enough to handle being a parent, they end up relying on the younger child for whom they have parental responsibilities, for emotional fulfillment. Sometimes this leads to sexual actions as well. Other abuse existing in the home greatly increases the likelihood of sexual abuse occurring. If children are used to being emotionally abused, or physically abused, they do not have healthy boundaries or understandings of their rights as a human being.
In the conservative christian homeschool worldview, sex ed is extremely lacking. We are talking about no knowledge of what sex is, human anatomy, etc. I grew up in this movement. My parents did not allow books in the house with such information. I remember when an art book from my grandparents included a nude sketch, my parents stapled several thick sheets of paper over it. I was told when I was 10 about menstruation, and that babies grow in a womb inside a woman’s belly with help from a seed from her husband. I was at several of my siblings home births. But that was it. When I was 17, I found a book in the library filled with pictures of fetal development, on one page it showed 2 thermal images of a penis showing how flaccid = cool, and erect/engorged = warm. This was the first time I was aware of the fact that erections were a part of (penis-in-vagina)sex. I went to a different section and found “Seventeen magazine’s girls guide to sex” and I put it inside of a large history book so no one could see what I was really reading and sat in the back corner on the floor reading as fast as a could. This was how I finally figured out that sex (the thing that only married people were supposed to do when they love each other very much, and was sinful and dirty otherwise) did not magically happen while 2 people slept in the same bed., and I was 17. I was 20 and married before I learned what a clitoris was. I had several children before I finally heard of the concept of “consent”.
This sheltering did not keep me from being a sexual person, It just left me with a complete lack information about it. I had no understanding of boundaries, or consent or even that masturbating was a sexual (albeit normal) act. My point is, that it is entirely possible to be a teenage conservative homeschooled kid, and have no idea what is sexual and what is not, or what is appropriate and what is not.
So no, given the circumstances of the home, combined with their belief system, I am not surprised by sibling incest. In fact, I think this happens in large conservative families far more than anyone thinks it does. What is truly horrifying, is that after setting their kids up for this to happen, Josh Duggar’s parents pushed it under the rug, kept things in house, and didn’t get help for either the molester or the children who were molested. Several of the headlines have claimed that Josh was turned in by his dad, this wasn’t true either. The investigation did not occur until over 3 years after, and only because an outsider got wind of it and called the abuse hotline. Jim Bob and Michelle did their best to cover up and move on. They claim because of god’s grace, the slate is wiped clean, as if it never happened. Except it did. It happens precisely because of the family system that has been paraded on TV for too long.
And it isn’t just the Duggars; this is basically the tip of the ice berg of what is out there in the conservative christian homeschooling movement. Despite the smiling wholesome-looking exterior, ignorance and repression and isolation creates this kind of set up again and again. When a system teaches that the victim is to blame, refuses to educate on or even talk about sex, treats children as property with no rights, and requires unquestioning obedience, it is not surprising when dysfunction comes to light.