Crotch Straps in Car Seats

Unless its totally closing off all blood flow to his boy parts, it won't cause future problems.

Also, you shouldn't wear bulky winter clothing in the car seat. I live in Minnesota, I know cold winters, but you never wear bulky clothing in the car seat. Read it in the car seat manual, it will say the same thing. Basically what happens in a crash is there is 3000+lbs of force put upon everything, and that puffy winter jacket will compress and that will make the car seat harness too loose, leaving your kid to be ejected or throw around violently.

If you doubt, try this. Put your child in the car seat with the jacket on, and buckle the car seat harness, and tighten it so you think its safe. Then, unbuckle and remove your child wihtout loosening the harness, and remove your childs jacket and rebuckle her into the car seat. All that slack in teh belt is what the harness would look like in a crash when the jacket compresses. If you sit on the jacket and it compresses, then imagine thousands of pounds of force on it in a crash.

A polar fleece is warmer than a puffy jacket and its car seat safe.

I'll just echo that kids shouldn't be in anything warmer than street clothes in the car for the same reasons people noted below-- if it is too cold, put them in the car seat and then put a blanket over them. Of course hats, boots, and mittens are fine.

does it hurt him? if it hurts then yes try a different car seat but only if he complains about discomfort

How big is her son? My 3 yr old used to cry about it in his old car seat we got the graco nautilus last winter and haven't had the issue since then and the crotch strap is still on the first slot we haven't moved it forward yet.
your edit: if he's not uncomfortable then he's fine my son is tight in his carseat and its not pushing on it and he is comfortable w/ his old car seat he used to cry that's we got a new one. Also you shouldn't be wearing puffy winter clothing it can compress in accident and the child could be ejected from the car seat.

All seats that I have seen have adjustments for the crotch strap, and it shouldn't be past the pelvic bone as that can cause damage in an accident. It should be in the position that will place it 'out from his body.

However one note. Please have her check into the issues with having winter coats buckled in the straps with children. It can be very unsafe if in an accident because it causes the straps to not be as tight as they need to be. There are documinated cases where children have been ejected from the seat but the coat is still buckled in. It is much safer to buckle them in w/o the coat and then put the coat on them backwards over the straps to keep them warm.

I have two preschool aged boys and I've never had a problem with this. I have their straps adjusted so that they are tight enough to hold them safely in their seats but not so tight that they are uncomfortable. I can't say I've ever really thought about 'long term effects' of an overly tight seatbelt. I'd have to imagine that the probability of that happening is pretty minuscule. Maybe some seats have the crotch buckle positioned in a spot that makes it uncomfortable for your friend's son. If he's taller than average, maybe his torso is too long for the standard fitting?? Not sure. I used a Graco seat when my boys were infants and then switched them to Britax Boulevard seats around 1 yr. The Britax seats come with a padded guard that goes around the crotch buckle as a cushion so maybe she could investigate those and see if they have what she's looking for.

We bought the Britax Marathon when my son turned 1 (he'll be 4 next week), LOVED the carseat ( thank goodness because it was almost 300).. About a month ago my son started complaining about his crotch hurting from it being too tight. What I DON'T like about the Marathon is that there's no adjustment for the crotch part to make it looser. So with that being said, I got rid of the car seat and had to go out and buy a new one that "had" adjustable crotch positions. Didn't spend that much this time around. Bought a Evenflo