Well actually, WE don't. But this petition does.
You can't fault the effort of the young lady that started the petition, Fernanda Schabarum, as it's certainly well researched and points out that females in the US make up over 40% of all football players according to the Department of State and 47% of game players according to the ESA.
How simple an addition this would be we just don't know, but I imagine the team would face some challenges in getting female players into the game. Maybe they could use TressFX if they did though? There could be benefits elsewhere too, if I could use some of the "enhancements" that would no doubt come along with the inclusion of female avatars to give my virtual pro some nice authentic man boobs, then that would be fine by me.
The petition is being sent to Brian Keaster, Director of Customer Service Operations at EA Sports and at the time of writing has 6,611 signatures, just over 12,000 short of it's 19,000 goal. If you'd like to add your support, you can do so on change.org.