http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1289%2Fehp.0901470

This is interesting. I think that what is happening is a disruption of the normal neurodevelopmental pathways that determine these things based on environment. An infant in a violent environment needs to be a more violent adult. The cycle of violence is well known, there must be physiology that mediates the cycle of violence and transduces exposure to violence into a more violent phenotype.

If phthalates are active in those pathways, then there is no threshold for them to exert an effect. The pathways are already actively regulating things, that is they are already in the “active range”. Anything that affects those pathways will affect the outcome.