COLOGNE, Germany—For years, Gamescom—one of the world's biggest annual trade exhibitions for digital gamers—has been a man's world.

But games developers now are increasingly targeting a growing community of female gamers, as a way of boosting an industry expected to generate sales of $100 billion this year.

"We see a big and fast increase in female players, over all genres," said Fredrik Rundqvist, a games producer at Ubisoft SA 's Massive Entertainment studio.