Hello I have the following experimental design: 12 samples, 6 are males 6 are females. Two conditions of treatment (Before and After) according to this table: |ID(subject)|sex|treat| |--|---|--| |1|M|B| |1|M|A| |2|M|B| |2|M|A| |3|M|B 3|M|A 4|F|B 4|F|A 5|F|B 5|F|A 6|F|B 6|F|A I found that there is a large gene expression variation among subjects from the same sex (ID). My assumption, based on biological observations, is that there should be genes that are deferentially expressed according to the treatment in the males but are not deferentially expressed in the females. What would be the right design to find those DEG. Thank you

For questions about how to choose and interpret an appropriate statistical design, I would recommend working with a local statistician or someone familiar with linear models in R.