A person's religion can often be perceived as a deeply ingrained part of their heritage and culture. If you hold a certain religion, it's likely that you'll want your child not only to share your beliefs but to also engage in the rituals and rites of passage of the religion.
If you are separated from the other parent of your child and you are working to share custody, it's likely that you'll have questions regarding your right to bring up your child in a certain religion, especially if your child's other parent does not share your religion. You'll also want to ensure that your child does not become confused and conflicted as a result of being taught different things by each parent.
Assessing the best interests of the child
The child custody courts proceed with caution when attempting to intervene on religious issues, since they do not want to trample on the rights of each parent to practice their own religion. Similarly, due to the First Amendment to the U.S. Constitution, courts cannot compare religions and decide which religion is better for the child than the other.
Generally speaking, courts will react positively toward a parent who wants to engage their child in a religious community. For example, if one parent wants to enroll their child in Sunday school and the other objects, the courts will likely deem it appropriate for the child to attend Sunday school, since it will help to improve their moral environment.
If you have found yourself in a dispute regarding religion with the other parent of your child, you should consider whether court intervention would be appropriate given the nature of the issue. Mediation can often be effective in handling such discussions.