Multiple Insert On Page_Load Event

Why is this simple insert runs twice on Page_Load event causing

page_______________
<%@ Page Title="" Language="C#" MasterPageFile="~/App_Masters/Content.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="ExecutiveReview_Default" %>
<asp:Content ID="Content1" ContentPlaceHolderID="PageStyles" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="PageContent" Runat="Server">
left black for test
</asp:Content>
<asp:Content ID="Content3" ContentPlaceHolderID="PageHelpContent" Runat="Server">
</asp:Content>
<asp:Content ID="Content4" ContentPlaceHolderID="PageScripts" Runat="Server">
</asp:Content>

protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack == false)
{
InsertLog();
}
}

private void InsertLog()
{
....executeInsert("insert into someTable (Col1) values ('test')");
}

now when once page is loaded there are two rows with test?