partner-contact/partner_contact_gender/views/res_partner.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
<data>

<!-- Declared the same in every module that may need it -->
<record id="base.personal_contact_information" model="ir.ui.view">
    <field name="name">Personal information page for contacts form</field>
    <field name="model">res.partner</field>
    <field name="inherit_id" ref="base.view_partner_form"/>
    <field name="priority">2</field>
    <field name="arch" type="xml">
        <data>
            <xpath expr="//page[@name='internal_notes']" position="after">
                <page name="personal_information_page"
                      string="Personal Information"
                      attrs="{'invisible': [('is_company','=',True)]}">
                    <group name="personal_information_group"/>
                </page>
            </xpath>
        </data>
    </field>
</record>

<record id="personal_contact_information" model="ir.ui.view">
    <field name="name">Partner gender: personal info</field>
    <field name="model">res.partner</field>
    <field name="inherit_id" ref="base.personal_contact_information"/>
    <field name="arch" type="xml">
        <data>
            <xpath expr="//page[@name='personal_information_page']/group[@name='personal_information_group']">
                <field name='gender'/>
            </xpath>
        </data>
    </field>
</record>

</data>
</odoo>