O'Brien family
The O'Brien family had Irish and Japanese heritage.

Miles and Keiko were married on October 24, 2367, after Data introduced them aboard the . ()

Their first child, Molly, was born in 2368. ()

After the O'Briens moved to Deep Space 9, their second child and first son, Kirayoshi, was born in early 2373 after being carried to term by surrogate mother Kira Nerys. ()

Members of the O'Brien family

Early history
Sean Aloysius O'Brien, an American union leader killed for his actions in the Anthracite strike of 1902.

24th century

Michael O'Brien, father of Miles and two other sons
His first wife. Together, they had:
Miles O'Brien and two other sons.
Keiko O'Brien, nee Ishikawa, wife of Miles. Together, they had:
Molly O'Brien
Kirayoshi O'Brien 
 Rita Tannenbaum, Miles' second wife in an alternate timeline. Their descendants included:
 Miranda O'Brien
 A man who was grandfather to:
 , Miles and Rita's great-great-great-great-great-granddaughter from that same timeline
His second wife
A cousin that Lisa Cusak reminded O'Brien of.
Families