On-line Te Reo Māori Dictionary

Ko Chris te tama a Richard rāua ko Gin.
Chris is the son of Richard and Gin.
Talking about more than one person - ...rāua ko..., rātou ko...

Ko Aria te tamāhine a Nikau rāua ko Ataahua.
Aria is the daughter of Nikau and Ataahua.
Talking about more than one person - ...rāua ko..., rātou ko...

Ko Angie te mātāmua o Richard.
Angie is the oldest child of Richard.

Ko te tuahine o Richard tērā
That's Richard's sister