<?php use_helper('Misc'); echo select_tag('sexo', options_for_select(Sexos(true), $alumno->getSexo()));
<?php use_helper('Misc'); echo select_tag('responsable[sexo]', options_for_select(Sexos(true), $responsable->getSexo()));
<?php use_helper('Misc'); echo select_tag('docente[sexo]', options_for_select(Sexos(true), $docente->getSexo()));