It is very common for men to live with children who are not their own. According to the U.S. Census Bureau, 1.8 million men reside with children they have not fathered or adopted.
Only about 60% of these men identify themselves as stepfathers, with the highest rates involving children who are teenagers. As a man living with your partner and his or her kids, what are your legal rights and options regarding the children?
As just the live-in boyfriend of your partner, you do not have any legal rights to the children. The parent may let you care for them, but you cannot make any legal decisions for them. This arrangement may be appropriate if you are in a new relationship or the other biological parent plays a significant role in the children's lives.
If you have married the parent of the children, then you can claim the title of stepfather. However, the marriage does not automatically grant you parental rights over the children. Rights to legal decisions can only come through you also becoming their legal guardian (or adoptive parent as explained next).
According to Missouri law, you do have the obligation to provide financial support to stepchildren, though this does not supplant the support the biological parent is responsible for. Neither does your income play a role in determining the amount of child support the natural parent must pay.
If you and your stepchildren have become close, you may be able to adopt them. However, this can be a challenge if the natural parent is alive because the person must give up all parental rights. Some parents agree to it, whereas others may put up a fight. The only way around it is to show the court that the biological parent is neglectful or abusive or has abandoned the children. If you are successful in the adoption, you will gain all rights a biological parent has, including in matters of divorce and inheritance.