OTTAWA — A Supreme Court ruling placing much of Canada's burgeoning fertility industry under provincial control leaves an enormous gap in the regulation of artificial procreation and exposes women who use the technologies and the children born from them to potential harm, critics say. A sharply divided court struck down key federal powers to regulate assisted human reproduction Wednesday, concluding that several parts of a new law fall under provincial jurisdiction over health care. The ruling effectively stops a federal move toward national standards and guts Assisted Human Reproduction Canada — an embattled federal agency that was struck four years ago to monitor how assisted procreation is carried out at more than two dozen fertility clinics across the country.