Wyoming law makes custody determinations based upon the best interests of the child and doesn't define an age to consider the child's wishes. The following is a WY statute:
20-2-201. Disposition and maintenance of children in decree or order; access to records.
(a) In granting a divorce, separation or annulment of a marriage or upon the establishment of paternity pursuant to W.S. 14-2-401 through 14-2-907, the court may make by decree or order any disposition of the children that appears most expedient and in the best interests of the children. In determining the best interests of the child, the court shall consider, but is not limited to, the following factors:
(i) The quality of the relationship each child has with each parent;
(ii) The ability of each parent to provide adequate care for each child throughout each period of responsibility, including arranging for each child's care by others as needed;
(iii) The relative competency and fitness of each parent;
(iv) Each parent's willingness to accept all responsibilities of parenting, including a willingness to accept care for each child at specified times and to relinquish care to the other parent at specified times;
(v) How the parents and each child can best maintain and strengthen a relationship with each other;
(vi) How the parents and each child interact and communicate with each other and how such interaction and communication may be improved;
(vii) The ability and willingness of each parent to allow the other to provide care without intrusion, respect the other parent's rights and responsibilities, including the right to privacy;
(viii) Geographic distance between the parents' residences;
(ix) The current physical and mental ability of each parent to care for each child;
(x) Any other factors the court deems necessary and relevant.
(b) In any proceeding in which the custody of a child is at issue the court shall not prefer one (1) parent as a custodian solely because of gender.
(c) The court shall consider evidence of spousal abuse or child abuse as being contrary to the best interest of the children. If the court finds that family violence has occurred, the court shall make arrangements for visitation that best protects the children and the abused spouse from further harm.
(d) The court shall order custody in well defined terms to promote understanding and compliance by the parties. Custody shall be crafted to promote the best interests of the children, and may include any combination of joint, shared or sole custody.
(e) Unless otherwise ordered by the court, the noncustodial parent shall have the same right of access as the parent awarded custody to any records relating to the child of the parties, including school records, activities, teachers and teachers' conferences as well as medical and dental treatment providers and mental health records.
(f) At any time the court may require parents to attend appropriate parenting classes, including but not limited to, parenting classes to lessen the effects of divorce on children.