Has always worked in IE
check this out in IE and see if you notice the increase in font size:
Code:
<style type="text/css">
.test {
position:relative;
top:50px;
left:30px;
height:50px;
font-size:15px;
}
</style>
<div class="test">Hello my baby</div>
<div class="test" style="font-size:30px;">Hello my baby</div>