At a Capitol press conference on Monday, four groups that fall under the label "advance practice registered nurses" said they can't prescribe medications in many situations, though they have the training to do so, because a 1989 law and subsequent amendments to it have created a quilt of outdated regulations that discourage doctors from supervising them as they prescribe. A study by Waco economist Ray Perryman that says nurse practitioners, certified nurse anesthetists, clinical nurse specialists and nurse midwives could fill many current gaps in the state's healthcare system—and help it survive an expected wave of 6 million newly insured Texans, if President Barack Obama's healthcare law survives.