Second Indigo Child

From Fahrenheit/Indigo Prophecy Wiki

The Second Indigo Child is the un-born daughter of Lucas Kane and Carla Valenti, and successor to Jade. She is currently gestating in her mother's womb, and as such doesn't have a name.

The child was originally concieved when her parents, succumbing to their respective feelings for one-another, had a passionate night of sex in a private area of the Camp of The Invisibles. Later, when they went to Wishita Military Base to confront the Purple Clan and Orange Clan one more time over Jade's secret, Carla follows Lucas inside and has the chance to give aid. Regardless of the outcome, Carla, unknowingly impregnated at the time, is irradiated with radiation from the Chroma Artifact. This means the child will have the same abilities as her father (who too received his abilities this way). Contrary to her predecessor, the child is meant to live and become the savior of humanity.

Carla discovered she was pregnant three months after the child's conception, by this time (regardless of the ending), Carla and Lucas were married and living together.