This theory is notoriously used by the military in many nations. By strengthening the in-group feeling you gain several traits such as increased confidence and feeling of belonging, and you increase tensions against the out-group which during a war is perceived as useful.
Benefits and drawbacks, one which many nations has gone with banning the practice of single sex education. I don't disagree with it and I find the science behind it to be rather robust.
Women have a tendency to be too empathetic and understanding and society tends to hang a lot of expectations on them to be so. If women want careers, being a little less caring and a little more goal oriented seems like a constructive outcome to me.
Where is the research on that?