Load Parent Theme CSS in Child Theme without using @import

functions.php

<?php
function twentytwelve_child_scripts() {
	wp_deregister_style( 'twentytwelve-style' );
	wp_register_style( 'twentytwelve-style', get_template_directory_uri() . '/style.css' );
	wp_enqueue_style( 'twentytwelve-child-style', get_stylesheet_uri(), array( 'twentytwelve-style' ) );
}
add_action( 'wp_enqueue_scripts', 'twentytwelve_child_scripts', 11 );