It is ethically recommended to obtain written consent from both parents, particularly if the study may have significant implications for the child or family. In the Informed Consent Form (ICF), two signature lines should be present.

Simultaneous signing is not required. The parent that is present at the on-site visit can take the ICF home which gives the other parent the opportunity to sign it too. Sufficient time should be given to participants and parents to consider before signing the ICF, allowing for both signatures to be obtained at a later time.

However, there may be situations where obtaining written consent from both parents is not feasible or appropriate, such as when one parent is unavailable (e.g.  when one parent is deceased, is in jail, in single-parent households,…), or estranged and there is no indication for the principal investigator (directly or indirectly) that the absent parent has a different opinion about the participation of the child in the study. In such cases, it may be ethically permissible to proceed with obtaining written consent from a single parent, provided that prior efforts have been made to involve and inform both parents and that the decision is made in the best interest of the child.

In that case, the parent that is present at the on-site visit should be asked if the co-parent would agree to the inclusion of the child in the study. If only one parent signs, it must be clear to that single parent that his/her written consent implies the consent of the other absent parent of the child/minor. It is good practice to document in the ICF that one parent signs on behalf of both parents, including the rationale behind.

If the principal investigator has knowledge of refusal of the other parent to allow the child to participate in the study, the principal investigator cannot include the child without the written consent of the other parent.

Ultimately, the ethical principle of respect for autonomy suggests that efforts should be made to obtain consent from all relevant parties whenever possible. However, it’s important to acknowledge that there are circumstances where both parents are not available. In such cases, it’s crucial to recognize that the remaining parent signs in their own capacity, not on behalf of both parents.

It’s essential to approach these situations with sensitivity and ensure that decisions are made in the best interest of the child.