Does Marijuana Affect Custody? Marijuana can affect custody in certain circumstances. Generally, what people think is because marijuana is now legal, it's no different than using or having the occasional cocktail or drink when you have a child custody situation at odds. What winds up happening is courts evaluate the level of marijuana, the frequency of use, and whether you're doing it around your children. A child custody attorney can attest that judges sometimes rule in a discretionary fashion on the best interest standards of children. I have seen judges rule that because you use marijuana in the house or around your children or around the custody of your children, you're simply using ...