One study looked at prenatal maternal use of cocaine, an opiate, marijuana, alcohol, and nicotine and sleep problems in the kids. Of these, only nicotine caused sleep problems. It's not so much that other drugs are turning out to be less damaging to fetuses than we thought (although there is some of that) as that tobacco is turning out to be worse than we thought.
In another study, mothers with bad enough anxiety to make them be taking selective serotonin uptake inhibitors during pregnancy had 3 year olds with increased withdrawal, anxiety, and depression. Some of it is due to a gene variant.
In another study, too much TV at 29 months of age is associated with all sorts of bad stuff in fourth grade:
"Each additional hour (per day) of television in early childhood corresponded to a
- 7 percent unit decrease in classroom engagement,
- 6 percent unit decrease in math achievement,
- 10 percent unit increase in victimization by classmates,
- 13 percent unit decrease in time spent doing weekend physical activity,
- 9 percent unit decreases in activities involving physical effort,
- 9 percent higher scores for consumption of soft drinks and
- 10 percent higher scores for consumption of snacks, as well as a
- 5 percent unit increase in BMI."
Another study looked at twin pairs where one weighed 20% more than the other at birth. The bigger twin was more likely to have conduct problems at age 3 or 4. The association was stronger with dizygotic twins than between monozygotic twins. So which thing causes which? Or more likely, what initial condition cascades to produce both of them.