<div class="row">
<div class="col-md-8">
<label for="Sexo">Sexo</label>
<div class="input-group"> <span class="input-group-addon"><i class="glyphicon glyphicon-user"></i></span>
<select name="Sexo" id="Sexo" class="form-control">
<option value="">Seleccione…</option>
<option value="1">Masculino</option>
<option value="2">Femenino</option>
</select>
</div>
</div>
</div>