Surf Zombie
GOLD
Rate of soccer ACL tears is higher - significantly, I think - with girls/women than with boys/men so that may be why you see parents of daughters in these discussions than parents of sons. One healthcare worker simplified one variable this way (I did not independently verify this claim): when boys enter puberty, their relative hamstring strength goes up while girls' relative hamstring strength goes down. We know that the quad:hammy balance is a critical variable in the risk of ACL tears so that sex-based difference may be a reason why we see differences (esp in non-contact scenarios).
I was told by my daughters surgeon (who does over 100 ACL surgeries per year on teenage girls) that the two big factors are the quad-hamstring strength ratio and the fact that when girls reach their teens the alignment of the hips and legs changes (which does not occur in boys) and that makes the girls more prone to knee ligament tears.