Other checkboxes in different rows are checked when a checkbox is checked

I have a grid and each row (300 of them) consists of "string | string | int | string | check." If for example I click on the checkbox in row 7, nothing out of the ordinary happens. But if I click another checkbox on another row, I may get 10 other rows with their checkboxes checked, but these other checkboxes arent executing the code associated with them.

            <DataGridTemplateColumn Width="*" Header="Add">
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>                           
                        <CheckBox Checked="CheckBox_Checked" Unchecked="CheckBox_Unchecked"/>
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
            </DataGridTemplateColumn>