INDIANAPOLIS (AP) _ A key Republican state senator is raising doubts about a proposal to expand Indiana’s private school voucher program by making it easier for siblings of those already in the program to also receive vouchers.
 
  The proposal would eliminate the requirement that the siblings of current voucher students first attend a public school for a year before becoming eligible for the program. Republican Sen. Carlin Yoder of Middlebury told the Senate education committee Wednesday that his bill prevents families from having to spend a year juggling with children in different schools.
 
  But Senate Appropriations Committee Chairman Luke Kenley questions whether that would be a fundamental change in the voucher program since when legislators approved it two years ago, the agreement was that all students would first give public schools a try.