partner_birthdate on this purpose.
@ -27,7 +27,6 @@
<field name="effective_date" attrs="{'invisible':[('member','=',False)]}"/>
</group>
<group>
<field name="birthdate" attrs="{'invisible':[('is_company','=',True)]}"/>
<field name="gender" attrs="{'invisible':[('is_company','=',True)]}"/>
</xpath>