The second reason used to justify controlling for sex is that genotyping/sequencing costs are prohibitive, making it extremely expensive to collect enough data to reach the sample size necessary to uncover sex differences. While this argument was once valid, the price of sequencing is rapidly declining, allowing for more samples to be collected and the all-important statistical power to increase. Further, large collaborative genetic consortia are collecting genotype/phenotype data and making it available to the scientific community at an increasingly rapid pace. As these datasets continue to expand, the availability of control/comparison samples as well as replication samples grows, again increasing statistical power. Declining sequencing cost combined with the growth of consortia and data sharing efforts should provide adequate sample sizes (at least control group samples) to start assessing sex in human genetics.
