Hospitals cannot legally conceal gender of fetus from mother

Apparently certain hospitals in Ontario are withholding the gender of a fetus from a mother to avoid a gender selective abortion. Ignoring any moral issues, is such withholding lawful?  No.

As a legal matter, absent legislation, such withholding is improper -- the patient is entitled to all medical information.

McInerney v. MacDonald [1992] 2 S.C.R. 138 held, in the absence of legislation, a patient is entitled, upon request, to examine and copy all information in her medical records which the physician considered in administering advice or treatment, including records prepared by other doctors that the physician may have received.

The physician-patient relationship is fiduciary in nature and certain duties arise from that special relationship of trust and confidence. These include the duties of the doctor to act with utmost good faith and loyalty, to hold information received from or about a patient in confidence, and to make proper disclosure of information to the patient.

The doctor also has an obligation to grant access to the information used in administering treatment. This fiduciary duty is ultimately grounded in the nature of the patient's interest in the medical records.
Information about oneself revealed to a doctor acting in a professional capacity remains, in a fundamental sense, one's own. While the doctor is the owner of the actual record, the information is held in a fashion somewhat akin to a trust and is to be used by the physician for the benefit of the patient.
The confiding of the information to the physician for medical purposes gives rise to an expectation that the patient's interest in and control of the information will continue. The trust-like "beneficial interest" of the patient in the information indicates that, as a general rule, she should have a right of access to the information and that the physician should have a corresponding obligation to provide it.