Michael,
Parental membership is not a prequisite for junior membership at any (except one) of the private clubs in my neck of the woods (Manitoba, Canada). The number of juniors accepted is limited, and the cost of said memebrship is more expensive than if their parents were members, but it's not prohibitively high. I'm actually surprised this question is being asked, I thought every club, except the most exclusive, allowed unattached juniors to join.
TK