UN Committee on the Rights of the Child (CRC), General comment No. 14 (2013) on the right of the child to have his or her best interests taken as a primary consideration (art. 3, para. 1)

The Committee considers that the elements to be taken into account when assessing and determining the child’s best interests, as relevant to the situation in question, are: the child’s views; the child’s identity; the preservation of the family environment and maintaining relations; care, protection and safety of the child; situation of vulnerability; the child’s rights to health and to education.

https://tbinternet.ohchr.org/_layouts/15/treatybodyexternal/Download.aspx?symbolno=CRC%2fC%2fGC%2f14&Lang=en