Consent is a process which allows individuals to indicate their willingness to participate in a research project.

Consent must be informed and voluntarily given. It signifies that individuals agree to participate in research of their own free will, after having been informed of all aspects of the research that could influence their decision. Relevant aspects include, the goals of the research, the risks and benefits of participating, the right to refuse participation, as well as the right to withdraw from the study.

The preliminary requirement of obtaining informed consent from research participants is a well-established and recognized procedure.

However, there are exceptional situations in which the requirement to obtain consent may be waived or altered. In these situations, a mechanism can authorize a research project without having expressly required that each participant’s consent be obtained.

Ethical and legal norms recognize certain conditions under which it is justifiable to have an exception to the requirement of obtaining consent. These conditions often vary from one norm to the other and from one law to another.

Here are some frequently encountered conditions:
•    The research project is important;
•    The research project is epidemiological;
•    It is impossible to contact potential participants;
•    The data or biological material has already been collected;
•    The anticipated risk is minimal;
•    The rights of the participant will be protected.

Often, more than one of these conditions will be required at the same time.

Mechanisms are generally provided to authorize an exception to consent. Their objective is to ensure the respect of the participant’s rights and interests.

These mechanisms are provided within the internal ethical norms and legislations of each country.

Among the existing mechanisms, we can frequently find the following:
•    Approval of the project by an ethics review committee
•    Examination of the legal conformity
•    Informing the participants or a group or representatives
•    The absence of opposition by participants.

• The Declaration of Helsinki (WMA, 2008) states that research subjects must be informed of the aims, methods, sources of funding, conflicts of interest, and potential risks and benefits of the research. It also states that consent must be obtained from research participants in writing.
• The International Declaration on Human Genetic Data (IBC UNESCO, 2003) provides that prior, free and informed consent is necessary for the collection, use and storage of human genetic and proteomic data, as well as other biological samples. It also outlines the information that must be provided to the person whose consent is sought, including: the purpose for which the data is collected, the risks and consequences associated with that collection and the right to withdraw consent.
• The Universal Declaration on the Human Genome and Human Rights (IBC UNESCO, 1997) states that prior, free and informed consent to research must be obtained.
• The International Ethical Guidelines for Biomedical Research Involving Human Subjects (CIOMS, 2002) requires researchers to obtain the voluntary informed consent of prospective subjects for all biomedical research.
• Resolution 2001/39: Genetic Privacy and Non-Discrimination (United Nations Economic and Social Council, 2001) urges States to ensure that genetic testing is done with the prior, free, informed and express consent of the individual or to ensure that authorization is obtained in the manner prescribed by law.
• The Statement on the Principled Conduct of Genetics Research (HUGO, 1996) states that informed decisions to consent to participate in genetic research can be individual, familial, or at the level of communities and populations.

Many international norms provide for the possibility of an exception to obtaining consent, under certain conditions.

For example:
•    The Declaration of Helsinki (World Medical Association, 2008) provides that an exception to consent can occur when it is unpractical or impossible to obtain consent, or when the obligation to obtain consent would jeopardize the validity of the study.  In these events, it is necessary that an ethics review committee’s authorization be obtained;
•    The International Declaration on Human Genetic Data (UNESCO, 2003) provides that an exception to obtaining consent may be permitted if the data that will be used is important to the study, for instance, in the context of epidemiological research. This exception must be provided in the internal legislation of the country concerned, and must be authorized by an ethics review committee.

·        The Tri-Council Policy Statement (CIHR, SSHRC, NSERC, 1998, 2000, 2005) requires free and informed consent and recognizes a right to return of results

The Tri-Council Policy Statement (Canadian Institutes for Health Research, Natural Sciences and Engineering Research Council of Canada, Social Sciences and Humanities Research Council of Canada, 1998, with 2000, 2002, 2005 updates) provides the general conditions that would allow an exception to obtaining consent:
•    The anticipated risk is minimal;
•    There is little risk that the study will affect the rights and well-being of the participants;
•    Research cannot be undertaken if consent is to be obtained;
•    If applicable, participants will be informed as soon as possible;
•    It is not a therapeutic intervention

This exception to obtaining consent must be approved by a research ethics committee.

• The Civil Code of Quebec establishes consent to research as mandatory (Art. 11). Article 22 states that consent must be obtained to allow a part of the body (such as an organ, tissue or blood) removed as part of care to be used for research purposes. This rule is important because DNA may be extracted from any cell in the living body. Article 24 provides that consent to research must be given in writing.
• The Énoncé de principes sur la conduite éthique de la recherche en génétique humaine concernant des populations (RMGA, 2003) emphasizes the importance of consent in population genetics research projects.
• The Statement of Principles: Human Genome Research (RMGA, 2000) provides guidelines for informed consent.

In Quebec, few laws authorize the use of personal information for research purposes, without necessarily obtaining the consent of the individuals concerned:
•    An Act respecting access to documents held by public bodies and the protection of personal information;
•    An Act respecting the protection of personal information in the private sector;
•    An Act respecting health services and social services.

The conditions provided in these acts are: that the use of the information will not be frivolous, that research cannot be done with anonymous data and that confidentiality will be protected.

This use must be authorized, either by the Commission d’accès à l’information or by the Director of professional services of a Quebec health care establishment.

All minors and some persons of full age are deemed legally incapable of giving their consent to research due to a reduced level of reasoning and comprehension, e.g. advanced Alzheimer’s patients. For minors and incompetent adults to participate in research, their legal representative must give consent. Other constraints may also apply. For example, the research may not involve a serious health risk for the participant, and the research must have the potential to produce benefit for the participant’s health or for other persons in the same age category or having the same disease or handicap. Additionally, an ethics committee must approve and monitor the research project.

Consent is generally considered to be a continuous process that can be withdrawn at any time. However, after a person has consented to the anonymization of his/her genetic data or biological samples, it is impossible to exclude these elements from research because the link between them and the person has been destroyed.

Research projects in the context of population genetics require consent from each individual participant. This consent is broad as concerns future, unspecified research purposes, subject to ethics review and governance.