Big Moshe Bernstein lived in Golders Green.
One day he bought a round of drinks for everyone in the bar because his wife Esther had just given birth to a typical ' Jewish' baby boy weighing 20 pounds.
Everyone in the bar congratulated him and many told him they found it hard to believe that his baby weighed in so heavily, but Moshe assured them "it's true, it's really true".
When Moshe came back to the bar some 3 weeks later, the barman asks "Hey you're the father of that typical ' Jewish' baby that weighed 20 pounds at birth aren't you? So tell us, how much does he weigh now?"
Moshe replies "12 pounds"
The barman says sorry to hear that and asks, "Why, what happened? Is he sick? Why has he lost so much weight?"
After swallowing a big swig of beer, Moshe wiped his lips with the back of his hand, leaned into the barman and boastfully replied, "We had him circumcised".