Passion Surge by Cynthia Sax

This cyborg never expected to become an instant father.
***
Surge is fascinated with newly manufactured offspring. He has studied them extensively, was one of the few medics present when the very first freeborn cyborg entered the universe.
He’s currently assigned to a battle station with an all-male crew. The probability of tending to an offspring is a dismal 0.0000 percent.
That changes when an unknown ship ventures into the sector they’re protecting.
Nu is an extremely exhausted single mom with a fussy newborn daughter. She has no time or energy for anyone or anything else. That includes a cyborg medic with gentle hands, brilliant blue eyes, and a voice deeper than space.
He claims she’s his female, the one being genetically designed for him. She has heard those types of declarations in the past.
Only a warrior without equal—and some much-needed rest—would prompt this universe-weary mom to believe in romantic love again.