ST. MARTIN'S PRESS is moving for a rehearing of the reversal of a 1977 ruling that had protected the company from prosecution for selling Show Me !, a sex education book for children, done largely in nude photographs of children and adults. Since its appearance in 1975, Show Me ! has been the object of considerable controversy, has sold 123,000 copies and has been prosecuted under state obscenity laws in Framingham, Massachusetts; Portsmouth, New Hampshire; Oklahoma city and Toronto, Canada. In the three states, charges were dismissed against the booksellers, the book being defined as "not obscene by law." In Toronto, where the case was brought against the Canadian publisher, Macmillan of Canada, the case was also dismissed. So, Show Me ! has never actually been on trial. But in 1977, New York State's penal laws underwent a change and one section, Section 263.15, dealing specifically with child pornography, became a source of anxiety to St. Martin's. This was a section that made it a crime to promote any performance of sexual conduct by a child under 16, and included photographs in books, even if they were not obscene. St. Martin's challenged the constitutionality of that law, and was granted a preliminary injunction against prosecution for Show Me ! But that injunction was overturned, which is why St. Martin's is asking for a rehearing. Although the sales of Show Me ! have leveled off, they are holding steady at about 1,000 a month; at this writing, the book is still in the stores. If St. Martin's motion is denied, says their counsel Roy Gainsburg, it's not clear yet what their next action will be.