"Several states have issued guidance addressed to individual taxpayers, informing them that while the state uses the federal income definition as the starting point for state income tax liability, same-sex spouses will not be treated as spouses at the state level.... However, this guidance does not address the responsibility of employers for imputing income on health benefits provided to same-sex spouses. Four states -- Nebraska, North Carolina, Ohio and Wisconsin -- have issued agency guidance that suggests employers impute income on health benefits provided to same-sex spouses. The income would be imputed for purposes of state income tax, but not for purposes of federal income tax."