The present findings should be interpreted in light of a number of limitations. First, the study focussed specifically on DNA methylation of annotated probes located within the CpG island of OXTR and it is likely that differences across groups may be found in other genes (e.g. glucocorticoid or serotonergic pathways; 52). While an epigenome-wide approach would have enabled us to examine group differences in DNA methylation across the genome (53), at present it is not plausible to build integrative developmental models, such as the one used here (i.e., with repeated methylation data included both as an independent variable and as a dependent variable), using a genome-wide approach, due to the computational burden of applying this method to hundreds of thousands of variables. Second, findings are based on a relatively small sample of youth with limited statistical power in view of the complex longitudinal models tested. Consequently, the present findings should be interpreted as well-grounded hypotheses for further examination in larger longitudinal studies. The use of larger studies may help to clarify the present findings, including (i) which aspects of prenatal
