Magento 2 Get custom attribute values in phtml

I want to populate attribute(Gender) values in select dropdown on listing page. On selecting specific value of the gender attribute, the product list should be filtered.

The gender attribute has 3 values

1. Male
2. Female
3. Others

For some products the attribute value is set to male and female as the product is unisex.

I want to know how can I get the values of attributes(male, female, others) irrespective of products.