"At U11, the 50-70 pound weight differential is legimate. You have 12-year old 5th graders who weigh 120-130 pounds (or more) playing aginst 9-10 year olds who often weigh between 65-80 pounds. I saw it this weekend."

it seems what you're describing is the traditional u9, u11,u13,u15 system. Under us lax age guidelines the oldest kids in u11 for spring 2015 will turn 12 this fall. the youngest would be 9 until next summer.

A grade based 5th grade team would have the kids born between 9/1/03 and 8/31/04, plus any kids who were held back. My experience having volunteered in rec lacrosse and seeing bdays is that the majority of kids who were held back from K or did pre 1st were summer birthdays. I have seen handful with spring and just a few with Jan/Feb. I've never seen a fall prefirst kid. Not to say it doesn't happen but would be rare even for the balto private schools. It does seem like it's a given if you're a summer bday you do prefirst at the gilman, st paul, Bls of the world. My point is that under grade based league tournaments it would be rare to have more than an 18 month spread between oldest and youngest.

The fairest system would be the one that soccer uses. Age by single year - u9,u10,u11,u12 etc. But the grade system detractors seem only to focus the holdbacks. In my opinion the 2nd fairest system is Grade. BTW my kids are in public schools, are in the proper grade age and 1 has a summer bday.

Bottom line is that no matter what system my july bday son is at a disadvantage for lax. But then he's one of the oldest for soccer because of July cutoff