a way that helper functions not produce XHTML but HTML?

I would like to use HTML 4.01 Strict, and used a DOCTYPE of it in my
application template. But look like when a style sheet is included by a
helper function

<%= stylesheet_link_tag 'style' %>

the code produced is XHTML:

<link href="/stylesheets/style.css?1243210734" media="screen"
rel="stylesheet" type="text/css" />

is there a way to ask Rails to use HTML instead of XHTML?

Nope, while it has been discussed a few times this is not something
rails supports. there might be a plugin for this out there.