親カテゴリ　分岐　

※なんかうまくいかなかった

ファンクションへ
タクソノミーだけなら下の部分だけでOK

/* For categories */
if ( ! function_exists( 'post_is_in_descendant_category' ) ) :
function post_is_in_descendant_category( $cats, $_post = null ) {
  foreach ( (array) $cats as $cat ) {
		// get_term_children() accepts integer ID only
		$descendants = get_term_children( (int) $cat, 'category' );
		if ( $descendants && in_category( $descendants, $_post ) )
			return true;
	}
	return false;
}
function post_is_in_category_slug($slug){
	global $post;
	$post_id = ( isset($post->ID) ) ? $post->ID : '';
	if ( in_category( $slug, $post_id ) || post_is_in_descendant_category( get_term_by('slug',$slug,'category'), $post_id ) ){
		return true;
	} else {
		return false;
	}
}
endif; //function_exists 'post_is_in_descendant_category'
 
 
/* For taxonomies */
if ( ! function_exists( 'post_is_in_descendant_taxonomy' ) ) :
function post_is_in_descendant_taxonomy( $terms, $taxonomy, $_post = null ) {
	foreach ( (array) $terms as $term ) {
		// get_term_children() accepts integer ID only
		$descendants = get_term_children( (int) $term, $taxonomy );
		if ( $descendants && has_term( $descendants, $taxonomy, $_post ) )
			return true;
	}
	return false;
}
function post_is_in_taxonomy_slug($slug, $taxonomy){
	global $post;
	$post_id = ( isset($post->ID) ) ? $post->ID : '';
	if ( has_term( $slug, $taxonomy, $post_id ) || post_is_in_descendant_taxonomy( get_term_by('slug',$slug,$taxonomy), $taxonomy, $post_id ) ){
		return true;
	} else {
		return false;
	}
}
endif; //function_exists 'post_is_in_descendant_taxonomy'

//宅
if ( post_is_in_taxonomy_slug('Cat-A', カスタムタクソノミー名) )
//具体例
<?php
  if (post_is_in_taxonomy_slug('ホームページ制作', cate_jirei) ):
?>
<?php endif; ?>

//カテ

if ( post_is_in_category_slug('Cat-A')