Suitable equipment for good protection
Your child may want to get kitted out like the goalies they see on the telly, in a short-sleeved jersey, shorts and no protective gear, but they need to protect themselves.
Explain to them that professional goalies touch the ball just 4 or 5 times during a match, on a pitch that's in perfect condition, but when they train, they protect themselves by wearing goalie's trousers, elbow and knee pads so they don't get injured and are able to play on the weekend.