Nat. Neurosci. 18, 690–697 (2015); published online 30 March 2015; corrected after print 8 February 2017

In the version of this article initially published, the Whole Genome Bisulfite Sequencing (WGBS) analysis was based on a data set in which one of the female .bam alignment files (FV2) was mistakenly truncated. This file has been removed from NCBI and updated with the raw reads. The realigned raw sequencing reads yielded the same alignment statistics as originally reported in Supplementary Table 5. The reanalysis did not change the main finding that females have significantly more fully methylated CpG sites in the POA than males and estradiol-treated females. In both analyses the reads were filtered for coverage, with a minimum of three reads per site per sample required for inclusion in the analysis. Thus reanalysis with the new, untruncated FV2 file meant that additional CpG and CHG sites became available for analysis across all samples. The analysis of this expanded data set showed a slightly different distribution of sex differences in CpG methylation across genomic regions (Fig. 1d) and chromosomes (Supplementary Fig. 3) than previously reported. After reanalysis incorporating the missing data, Figure 1c,d and Supplementary Figures 2 and 3 have been replaced. In the first Results paragraph, “females had nearly twice the level of fully (100%) methylated CpG sites as males or masculinized females” has been replaced by “females had nearly 50% more fully (100%) methylated CpG sites as males or masculinized females”; “sex differences were generally dispersed across chromosomes, although methylation on chromosome 5 and 13 was biased toward females and males, respectively” has been replaced by “sex differences were generally dispersed across chromosomes”; and “The overwhelming majority of CpG sites exhibiting a sex difference in methylation were in intergenic regions (∼84%), followed by introns (∼14%), promoter regions (∼2%) and exons (<1%)” has been replaced by “The overwhelming majority of CpG sites exhibiting a sex difference in methylation were in intergenic regions (∼69%), followed by introns (∼26%), exons (∼5%) and promoter regions (<3%).” In the Figure 1c legend, “F(2,6) = 6.594, P = 0.0306” has been replaced by “F(2,6) = 5.67, P = 0.041.” In the Figure 1d legend, “1,242 sex differences” has been replaced by “2,748 sex differences.” In the Supplementary Figure 2 legend, “*p < 0.05” has been changed to “**p < 0.01.” Under Supplementary Figure 2a, “F%meth(9,60) = 709.2” has been changed to “F%meth(9,60) = 1244”; “Fsex(2,60) = 5.047, p = 0.0094” has been changed to “Fsex(2,60) = 2.885, p = 0.0636”; “Males and estradiol-treated females had a greater number of CpG sites 80–90% methylated compared to females (Tukey's HSD, p < 0.0001)” has been changed to “Males (Tukey's HSD, p < 0.0001) and estradiol-treated females (Tukey's HSD, p = 0.0014) had a greater number of CpG sites 80–90% methylated compared to females”; and the final p value has been changed from 0.022 to 0.0055. Similarly, under Supplementary Figure 2b, “F%meth (9,60) = 4787” has been changed to “F%meth (9,60) = 8959”; “Fsex (2,60) = 7.514, p = 0.0012” has been changed to “Fsex (2,60) = 12.73, p < 0.0001”; “male vs. female + e p = 0.0003” has been changed to “male vs. female + e p < 0.0001”; and “Fint(18,60) = 17.16” has been changed to “Fint(18,60) = 23.8.” In the Supplementary Figure 3 legend, “Overall, male chromosomes were more hypomethylated relative to females (χ2= 47.83, n=21, p = 0.0004),” has been changed to “There were no overall differences in CpG methylation by chromosome (χ2 = 30.97, n=20, p = 0.0556).” The errors have been corrected in the HTML and PDF versions of the article.