Colorado uses the term “parental responsibility,” not custody. This refers to decision making responsibility, and it refers to a parent’s authority to make major decisions about a child’s overall welfare like health decisions, religious activities, and education. It can be shared jointly, awarded to one parent or divided. Divorcing parents may agree on parental responsibility for themselves, which they will document for the court in their separation agreement or parenting plan.  If no agreement is reached, the decision will be left to the Court using the standard of what is in the best interests of the child.