In what ways are the novel and its protagonist affected since virtually no women are included? Would a writer today exclude women in a war novel?

The American Civil War was a conflict fought by MEN. Although there are a few rare examples of women who disguised themselves as men so they could fight, the woman's role on the battlefield was practically non-existent. Some wives did follow their men (sometimes travelling in wagons or on horseback)when units moved out, but they were restricted to far beyond the battle lines. Prostitutes also emerged during the war, following many Union armies to ply their trades during the soldiers' off-hours, but they were also not present when action was expected. Crane's story tells of a bloody battle and the reactions of a unit of first-time soldiers engaging in their first action. There is little place for women in this scenario, so Crane wisely left them out of the narrative.

Sadly, most modern writers would include women for the romantic angle that could be developed. Of course, women play a much larger part of active military units throughout the world today than during Crane's time.