What does no gender specific nouns mean?

A 'gender specific noun' is a noun for a male, a female, or a thing.

A 'non-gender specific noun', also called a common gender noun is a Word for something that can be either male or female. Examples:

Gender specific nouns:

nouns for a male: man, father, brother, uncle, king, stallion

nouns for a female: queen, daughter, wife, niece, doe, hen

nouns for things that have no gender: house, plane, bicycle, hamburger, planet, water

non-gender specific nouns:

common gender nouns: parent, friend, teacher, doctor, neighbor, manager