Couples whose lawsuits against fertility providers led an Alabama court to rule that frozen embryos could be considered children have asked a judge to toss out a new state law that provides legal immunity to in vitro fertilization providers.

The couples asked the judge to declare that the law—which was hastily approved by state lawmakers to protect IVF services in the state—as unconstitutional. It is the latest development in the legal saga that drew international attention and sparked concerns over the availability of IVF.