Populating a span with a string including a linked email

Question

I'm trying to have have this span have the text below with the email being an active link. But it just prints the entire text as a string including the HTML mark-up. Do I need to escape it some other way?

ASPX file:

  <span id ="Email" runat="server"></span> 

Code Behind:

  Email.InnerText =  "Email responses here:<a href='mailto:this@that.com'>this@that.com</a>";