It depends. If there is an existing custody order, the non-custodial parent must file a petition to modify the existing order. If there is no custody order and the parents are married, a petition to dissolve the marriage must be filed. If there is no custody order and the parents were never married, the nature of the petition depends on whether the petitioner is the mother or father. the mother can file a petition to establish paternity and ask for temporary orders giving her custody. If the father files the petition, the proper procedure depends on whether or not the dad is a "presumed father" as defined by the parentage statute. As you can see, the statutes and cases on child custody are numerous and complicated. You should consult with an experienced family law attorney before you start any court case.
DISCLAIMER: This answer is provided for general educational purposes only. By using or participating in this site you agree and understand that there is no attorney client privilege between you and the attorney responding. The law changes frequently, and varies from jurisdiction to jurisdiction. The information provided in this answer is general in nature, may not apply to the factual circumstances described in your question, and may be different in the State where the facts occurred. For a definitive answer you should seek legal advice from an attorney who (1) is licensed to practice in the state which has jurisdiction; (2) has experience in the area of law you are asking about, and (3) has been retained as your attorney.
If being with the father is not in the best interest of the child, the court may end up having the child placed somewhere else.
The choice for the court is not simply between the two parents but what is in the best interest of the child.
For example, if the father had a conviction of abusing the child, the court likely would never allow the father to get custody of the child.
The father should review his specific facts with his attorney to find out his legal options.
In Washington, one parent is designated the primary residential parent, the other is designated the alternate-residential parent. They are equal in their rights and obligations as parents unless there are restrictions identified in a court order. Assuming that there are no restrictions on the father, he has the same right as any other parent to care for his child. If there are restrictions, he needs good legal advice before he does anything else.
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