Why West Germans must call their little 'Rasputin' Hans

What's in a name? The question on which Shakespeare's Juliet soliloquized is a big nuisance for West German registrars. For a growing number of West German parents are giving their children names which, when they grow up, could turn into millstones around their necks. It seems that many parents would rather call their babies a bizarre or original name, even if they have to invent it, than resort to the traditional Hans, Klaus , or Helmut, Anna, Dorothee or Marion.

Unlike France, which insists that children's names figure in the calendar of saints, West Germany allows parents to call their kids whatever they like, as long as the names ''remain within the framework of public morals and order'' - according to a verdict of the federal supreme court.

That ruling was sufficiently vague to leave much to the discretion of the town or village registrar, whose verdict can be challenged through a whole series of courts. Cases sometimes take years.

Among names recently accepted are Pepsi-Carola (for a girl) and Rasputin (for a boy).

Other parents have not been so fortunate. A Hamburg judge recently denied one couple the right to call their son ''McDonald'' (since it is a corporate name). Attempts to name children ''Agfa'' (a type of camera), and ''Omo'' (a soap powder), have also been rejected.

The latest test case comes from the state of Rhineland-Palatinate, where registrar Karl Seidel refused Manfred and Marion Hessler the right to call their baby boy ''Pumuckl,'' the name of a popular cartoon dwarf on television.

''Where will it all end?'' sighed Seidel. ''Next we'll have parents wanting to call their child 'E.T.' ''

The Hesslers do not agree. They feel their basic liberties have been violated by the decision and are prepared to take the case to the Federal Constitutional Court if necessary to obtain justice. The child is five months old and still does not have a name.

Several West German parents, apparently weary of the drab republicanism of their country, have tried and failed to give their children noble names with built-in titles. Among those recently turned down are ''Princess Anne,'' ''Baron ,'' and ''Lady Diana.'' But a Dortmund family won their case against a registrar who had refused to let them call their son ''Merlin,'' after the wizard of English legend - a name to conjure with.

Whether that little boy will thank his parents when he grows up is open to question. Perhaps he will be consoled by Humpty Dumpty's answer to Alice in Lewis Carroll's ''Through the Looking Glass.'' When Alice tells him: ''With a name like yours, you could be any shape, almost,'' the wretched egg-shaped creature replies: ''They gave it me - for an un-birthday present.''