Researchers at the University of Pennsylvania School of Medicine found that children in single-parent households were twice as likely than other peers to be sexually abused. This is usually because parental absence from home leaves more opportunity for sexual predators to come closer to children and eventually abuse them.

When adjusting for socioeconomic factors, children in single-parent families were still at greater risk of being sexually abused than children with two parents, especially those who came from low-income homes.
However, children from single-parent families are not just at risk of sexual abuse, they are also at bigger risks of health problems like poorly controlled diabetes and asthma.

Since single parents need to provide for the family, they are often away. This leaves children to seek an adult with whom to share experiences and bond. This is where sexual predators come into the picture. They set children up over time, earn their trust, act as parent-substitutes, give them attention and gifts so that children could learn to trust them.
Predators are really good at finding these sorts of kids.

The conclusion of this and other studies is that single parents should be given more support and improved access to quality child care. Unfortunately, the reality is far from this picture.