According to the Hamilton Spectator, 11 July 2014, "The Pan Am tournament is limited to players born on or after Jan. 1, 1993, which in soccer parlance is referred to as U-22. Oddly, though, the six teams that have to qualify — one from the Caribbean, one from Central America and four from South America — must do so at regional U-20 tournaments, because there aren't equivalent U-22 events. The teams that do make it through, can then add older players for the Pan Ams. [...] The U.S. will not send a team in either the men's or women's division, partly because so many of their players have club commitments. That leaves Canada, as the host country, and Mexico as the automatic qualifiers from North America for both the men's and women's tournaments."
Good news is that, this time again, there won't be a clash of calendars with U20 World Cup. I hope no U17 teams.
The Pan Am Games will start only four days after the final of the 2015 FIFA Women's World Cup is played. Because of this, Canada will probably not play with the women's national A team but with the women's U23 team. (Hamilton Spectator, 10 August 2012
(Note that Hamilton is where the football tournament of the 2015 Pan Am Games is played).