Radio button assignment snafu

[Chumley the Walrus]

I'm trying to parse the selected value from a group of radiobuttons,
but the below code for the radio buttons doesnt work, whereas the one
for the text box does.
<% dim dateinbox, sportsel
dateinbox = TextBox1.text
sportsel = Sport.text %>

<asp:TextBox id="TextBox1" runat="server"></asp:TextBox>

<asp:RadioButton id="sport1" GroupName="Sport" text="mlb" value="mlb"
runat="server">
</asp:RadioButton>
<asp:RadioButton id="sport2" runat="server" GroupName="Sport"
text="nfl" value="nfl" /></asp:RadioButton>

...if i try to assign the same id "sport" to the radio buttons, i get
a "there is already an ID with the name 'sport' error

?????