"Mother" and "father" in French?	La mère, le père. Informally: maman, papa.
"Parents" in French?	Les parents. Parents can also mean relatives in general: un parent éloigné is a distant relative.
"Son" and "daughter" in French?	Le fils (the s is pronounced: "feess"), la fille. Fille also means girl.
"Brother" and "sister" in French?	Le frère, la sœur.
"Grandfather" and "grandmother" in French?	Le grand-père, la grand-mère. Les grands-parents means grandparents.
"Grandson" and "granddaughter" in French?	Le petit-fils, la petite-fille. Les petits-enfants means grandchildren.
"Uncle" and "aunt" in French?	L'oncle (m.), la tante.
"Cousin" (male and female) in French?	Le cousin, la cousine.
"Nephew" and "niece" in French?	Le neveu, la nièce.
"Husband" and "wife" in French?	Le mari, la femme. La femme means both woman and wife: ma femme is my wife.
"Boyfriend" and "girlfriend" in French?	Le copain, la copine (everyday). Le petit ami, la petite amie (clearer, slightly formal).
"Father-in-law" and "mother-in-law" in French?	Le beau-père, la belle-mère. The same words also mean stepfather and stepmother.
"Brother-in-law" and "sister-in-law" in French?	Le beau-frère, la belle-sœur.
"I'm an only child" in French?	"Je suis fils unique" (male) / "Je suis fille unique" (female). No article after suis.
"Twins" in French?	Les jumeaux (boys or a mixed pair), les jumelles (girls).
"Man, woman, child" in French?	L'homme (m.), la femme, l'enfant (m. or f.: un enfant, une enfant).
"Baby" in French?	Le bébé. It stays masculine even for a baby girl.
"Friend" (male and female) in French?	L'ami, l'amie. They sound identical; only the spelling shows gender. Informal: le pote.
"Neighbour" in French?	Le voisin, la voisine.
"How many brothers and sisters do you have?" in French?	"Combien de frères et sœurs as-tu?" "J'ai un frère et deux sœurs."
"I'm married" in French?	"Je suis marié" (male) / "Je suis mariée" (female). Divorced: divorcé(e). Single: célibataire.
"My older sister" and "my younger brother" in French?	Ma sœur aînée (or ma grande sœur), mon frère cadet (or mon petit frère).
"To get along well with" in French?	S'entendre bien avec. "Je m'entends bien avec ma sœur."
"A big family" in French?	Une famille nombreuse, usually a family with three or more children.
"Godfather" and "godmother" in French?	Le parrain, la marraine.