From the above considerations, the mathematical models and explanations presented in this paper demonstrate that decreases of oxytocin and oxytocin receptors may provide an explanation for the ubiquitous presence of impaired social interaction in all the neurological disorders encompassing autism, whereas the ubiquitous presence of repetitive behavior would have other explanations, perhaps related to neural circuitry and/or synaptic dysfunction. This evidence concerns the gene OXT and autism.