Is it illegal for a 3 yr old girl to sleep in the same bed as her single father?

There is no federal law in the United States that specifically addresses whether or not a 3 yr old girl can sleep in the same bed as her single father. However, some states have laws that prohibit co-sleeping between adults and children, and these laws may apply to single fathers. For example, the state of California has a law that prohibits any person from knowingly allowing a child under the age of 8 to sleep in the same bed as an adult, unless the adult is the child's parent or guardian. It is important to note that these laws vary from state to state, so it is important to check the laws in your specific state to determine if there are any restrictions on co-sleeping between adults and children.