If the biological mother fails to perform the maintenance obligations, she may not ask her children to perform the maintenance obligations. If children can produce evidence to prove that their biological mothers have not fulfilled their obligations, they can refuse to fulfill their obligations. Children can be exempted from the obligation to support when the following circumstances occur. (1) Unmarried or divorced adult children have no economic income, lose labor or cannot live independently; (2) Married adult children themselves have no economic income, and their family income is not enough to maintain the local basic living standard. (3) Parents have committed serious crimes against their daughters. For example, if a parent commits the crime of killing a child, seriously abusing a child, or abandoning a child, and loses the right to ask for support from the murdered child, the child may be exempted from the obligation of support. If the victim's children voluntarily support, the law does not prohibit it. According to the second paragraph of Article 2 1 of the Marriage Law, minors or children who cannot live independently have the right to ask their parents to pay alimony when their parents fail to perform their alimony obligations.