BOSTON - The governor's office has instructed hospitals to cross out the word "father" on birth certificates for children of same-sex parents and substitute "second parent," angering municipal clerks. Eric Fehrnstrom, a spokesman for Gov. Mitt Romney, said Thursday that the certificates are perfectly legal. But municipal clerks, who register and store birth records, say the cross-outs could leave the documents open to challenges by passport agents, foreign governments and other officials. "They should not have a birth certificate that has crosses on it," said Barnstable Town Clerk Linda E. Hutchenrider, a past president of the Massachusetts Town Clerks Association....