Formal:
* Mes cousins: This is the most common and general way to say "my cousins."
* Mes cousines et mes cousins: This emphasizes that you have both male and female cousins.
Informal:
* Mes cousins: This is also used informally, but it's more common to use the specific gender:
* Mes cousines: My female cousins
* Mes cousins: My male cousins
With a possessive adjective:
* Ma cousine: My (female) cousin
* Mon cousin: My (male) cousin
* Ses cousins: Her/his cousins
Examples:
* "J'ai beaucoup de cousins." (I have a lot of cousins.)
* "Je vais voir mes cousins ce week-end." (I'm going to see my cousins this weekend.)
* "Ma cousine est très gentille." (My female cousin is very kind.)
Remember to choose the right form based on the context and your relationship with your cousins.