My language, Verbum, uses a series of prefixes and suffixes to change the meaning of a root word. So for example the root word for MAN is ma. From ma, most, if not all other formal relationships to a man can be created. But first a quick prefix/suffix overview:

her/hēr - lower and high ranks

nō - Plural

ke - Classification

rū - Child of/Parent of, rē - Joint/Equivalent relationship

ga - increased/improve or greater condition, sa - an extreme/intensive amount/representation

Now for the Words... ( all made from the same root).

Man/male/males – ma/mam/mamnō

Men – manō

Woman/female/females – mana/manal/manalnō

Women – mananō

Boy – herma

Girl – hermana

Person – kema

People – kemanō

Child – herkema

Toddler – gaherkema

Baby/Newborn – sagaherkema

Children – herkemanō

Elder/senior citizen - kemahēr

Son – rūma

Daughter – rūmana

Father – marū

Mother – manarū

Wife – rēmana

Husband – rēma

Grandfather – gamarū

[Great] Grandfather – sagamarū

[Great] Grandmother – sagamanarū

Grandson – garūma

Grandaughter – garūmana

Brother - marē

Sister - manarē

Aunt – manarēhēr

Uncle – marēhēr

Cousin (male) – gamarē

Cousin (female) – gamanarē

EDIT: how does your language handle these words