But no more. The two dolls are about to find themselves thrust into a world of harsh materialism, where money is the driving force and market domination the aim. Next year, they will launch what promises to be a bitter, cut-throat and expensive legal battle over an issue of no less importance than the shape of Sindy's cranium.
Not, of course, that lawyers involved in the case confess to seeing matters in this light. The issue, they say, revolves around 'passing-off' and the damages could run to millions of pounds.
At a hearing in January, a High Court judge will spend about five days listening to barristers thrash out the arguments. The losers may have to pay a six-figure sum in costs alone.
The action has been brought by Barbie - makers, Mattel Inc - who says that Sindy - makers, Hasbro Industries - underwent plastic surgery in an attempt to look like her.
In the 1960s, it appears that Sindy was a demure creature, wearing tweeds and twin-sets, and interested mainly in horses. Barbie was anything but demure, wore glitzy dresses and had an overriding interest in her boyfriend, Ken.
And which image was more compelling? Sindy has annual sales worth pounds 7m, while Barbie's are worth pounds 300m - 20 times the earnings of Madonna. It was these figures which prompted Hasbro to transform Sindy into a Barbie lookalike, according to Mattel. This, the company says, is an infringement of copyright. Hasbro disagrees, maintaining that its doll has undergone gradual change in line with the 'growing sophistication' of today's youngsters.
On Wednesday, at a pre-trial hearing, Mr Justice Aldous agreed that lawyers should travel to the US to obtain evidence from the woman who sculpted Barbie's features in 1976. Joyce Clark's evidence will be put on videotape, which will be shown at the January hearing if she is unable to attend.Reuse content