What is the age at which participants can consent to take part in research?

Legal Age

There is no legal age of consent for research studies in Ontario.

University of Guelph Students

For the majority of studies which recruit University of Guelph students, students can consent on their own behalf, even though they may not yet be 18 years old. It is deemed that they have sufficient capacity to make this determination (in most cases).

Clinical Trials

Health Canada indicates that the age of consent is 16 to 18 years of age (18 in Quebec). This would apply to studies which will undergo review by Health Canada.


From TCPS2(2022) Interpretations

TCPS 2 does not specify an age of consent for children. Seeking consent from children is not based on their age, but on whether they have the capacity to understand the significance of the research and the implications of the risk and benefits to themselves – as defined in TCPS 2 Section 3.C. Factors to consider in making the decision to seek consent from children as participants include, but are not limited to, the nature of the research, the research setting, the level of risk the research may pose to participants, provincial legislation and other applicable legal and regulatory requirements related to legal age of consent, and the characteristics of the intended research participants - who may differ in many aspects including their capacity to make their own decisions. As no two research studies or research participants are identical, the decision to seek consent from children instead of an authorized third party should be considered on a case-by-case basis. In practice, the researcher plays a key role, sometimes in association with the parents, in determining whether the child is able to consent.

The REB is increasingly open to allow children between the ages of 12 and 17 to consent on their own behalf for research projects which inquire into subjects over which an individual of that has agency to decide. The decision of whether or not parental/guardian consent will be required should be determined on a case by case basis after considering the research topic and the context of the project. For a more nuanced discussion please see the TCPS2(2022), Chapter 3, Part C


Article 3.3 application indicates that rather than an age-based approach to consent, researchers should consider the capacity of the individual. To determine if participants have the capacity to consent on their own behalf, researchers should consider if they have the capacity to fully understand the risks of the research project, including risks to privacy. 

Consent of Parent/Legal Guardian

From the TCPS2: 

Article 3.9 For research involving individuals who lack the capacity, either permanently or temporarily, to decide for themselves whether to participate, the REB shall ensure that, as a minimum, the following conditions are met:

  1. the researcher involves participants who lack the capacity to decide on their own behalf to the greatest extent possible in the decision-making process;
  2. the researcher seeks and maintains consent from authorized third parties in accordance with the best interests of the persons concerned;
  3. the authorized third party is not the researcher or any other member of the research team;
  4. the researcher demonstrates that the research is being carried out for the participant’s direct benefit, or for the benefit of other persons in the same category. If the research does not have the potential for direct benefit to the participant but only for the benefit of the other persons in the same category, the researcher shall demonstrate that the research will expose the participant to only a minimal risk and minimal burden, and demonstrate how the participant’s welfare will be protected throughout the participation in research; and
  5. when authorization for participation was granted by an authorized third party, and a participant acquires or regains decision-making capacity during the course of the research, the researcher shall promptly seek the participant’s consent as a condition of continuing participation.


When appropriate, you are encouraged to fully involve children in the consent process for studies in which they will be participating. While children are often not in a position to ‘consent’ to the research (i.e. they are not capable of making a truly informed decision), they should be told what is happening and what their rights are. In lieu of ‘consent’, minor children may sign documents indicating that they ‘assent’ to the research. See TCPS2(2022), Chapter 3, Part C for discussion of determining the decision making capacity of participants.

 This can be accomplished in three ways:  

  • They may sign the regular study consent document, or; 
  • They may sign a separate ‘assent’ document with wording more appropriate to their age and comprehension level, or;
  • They may provide verbal assent.

Assent forms should be written at the appropriate educational and maturity level of the youngest prospective participant. Techniques such as the use of larger type, simple schema, and pictures may help boost a child’s understanding of the text. Depending on the age range of the minors to be involved, you may want to consider submitting two different assent forms at different reading comprehension levels. The general rule is to provide one assent form written for young children between the ages of 7 and 12 years of age, one assent form written for teenagers between the ages of 13 and 18 years, and a verbal assent script for those younger than 7. 

An assent form should contain date and signature lines for the child and the person obtaining consent. 

See below for an example of an Assent Form. Please note:  the sample is not meant to serve as a template. Assent forms must be tailored to the reading and comprehension level(s) of the subject populations to be enrolled and will vary widely from study to study.

An assent form should contain date and signature lines for the child and the person obtaining consent. The assent form should over the following points: 

  • What the study is about
  • Why the child is eligible to participate in the study
  • What procedures will be performed
  • Who will know they took part in the research
  • Who will know what they said
  • Potential risks and discomforts to the child
  • Potential benefits to the child or society
    • Usually no direct benefit to the child, but perhaps to children like them.
  • For non-therapeutic research, a statement that the child can choose whether to participate and may withdraw at any time without negative consequences
  • An invitation to ask questions any time
  • An indication of whom to contact with questions. 

Sample Assent For Children Seven to Ten 

--University of Guelph Letterhead— 

Study Title 

Investigator’s Names 

Why am I here?

The researchers want to tell you about a study about how to help children who do not like school. They want to see if you would like to be in this study. Jane Doe and some other researchers are doing this study. 

Why are they doing this study? 

They want to see if certain things, more than others, make you like going to school.

What will happen to me? 

If you want to be in the study two things will happen: 

1. Every 3 months while you are in grade 4 you will be asked some questions by the researcher about how you like school. 

2. You will go on a field trip to the museum. 

Will there be any tests? 

No, there will not be any tests or marks on the report card. 

Will the study help me? 

No, this study will not help you directly but in the future it might help children who are having trouble with math. 

Who will know what I say to the researchers?

Your teachers and parents will not know what you say to the researchers. Your name will not be used in the results. But if you tell the researchers about someone trying to hurt you, they will have to tell people in order to get you help.

What if I have any questions? 

You can ask questions any time, now or later. You can talk to the teachers, your family, or someone else. 

Do I have to be in the study? 

You do not have to be in the study. No one will be mad at you if you don’t want to do this. If you don’t want to be in this study, just say so. Even if you say yes now, you can change your mind later. It’s up to you. 


I want to be in this study 

Print name of Child: 
Signature of Child:

Support info
Human Ethics
Recruitment and Consent