The below made sense for 2013. However, now, I would use the :not() selector as described below.
CSS can be overwritten.
DEMO: http://jsfiddle.net/persianturtle/J4SUb/
Use this:
.parent {
padding: 50px;
border: 1px solid black;
}
.parent span {
position: absolute;
top: 200px;
padding: 30px;
border: 10px solid green;
}
.parent:hover span {
border: 10px solid red;
}
.parent span:hover {
border: 10px solid green;
}<a class="parent">
Parent text
<span>Child text</span>
</a>