A mother holds hands with her son on a swing set. At least seven states have passed laws making equally shared parenting time the legal default in child custody cases. (Photo by Troy Bennett for Maine Morning Star) A growing number of states are making an equal split between parents the default child custody option in divorce cases. Louisiana and Mississippi this year joined at least five other states that have adopted the so-called 50-50 standard — four of them since 2021, as more legislators rework divorce-related laws that remained mostly unchanged for years. The 50-50 custody issue does not break down cleanly along partisan lines: The Mississippi bill was sponsored by Republicans, the Louisiana legislation by Democrats. Both states’ laws explicitly codify a custody guideline that many courts in other states follow. Supporters say a formal 50-50 custody standard makes divorce proceedings more equitable for fathers — who historically have been awarded less custody time than mot...