Blond joke

[Big N' Blue]

A blonde chick gets a job as a physical education teacher of 16 year olds..
She notices a boy at the end of the field standing alone, while all the other kids are running around having fun, kicking a football.
She takes pity on him and decides to speak to him.
'You ok?' she asks.
'Yes,' he replies.
'You can go and play with the other kids, you know,' she says.
'It's best I stay here,' he says.
'Why's that, sweetie?' asks the blonde.
The boy looks at her incredulously and says: "Because I'm the goal keeper !!!"