Mariah and Nick welcomed twins - a boy and a girl - on their third wedding anniversary.
A spokesman for the pair said that they were "overjoyed" at their new arrivals, which weighed in at 5lbs 3oz and 5lbs 6 oz respectively.
She also revealed that Mariah listened to her own song, We Belong Together, as she was giving birth.
The couple, who renewed their wedding vows while in hospital, have named their little girl Monroe, after Mariah's inspiration Marilyn Monroe, and their son, Moroccan, inspired by the country where Nick proposed to the star.
Tools designed to ensure computer code in smart cars does not crash has been inspired by hungry penguins.
The rounded sleeping capsules send guests drifting into ocean before arriving on desert island by morning.
Sitting on the saddle activates the part of the brain responsible for learning, a study has claimed.
Scientists are appealing for more people to donate their brains for research after they die.
Life on Earth may have arrived from Mars on an asteroid, scientists have claimed.
Lunar mission scheduled at the end of 2017 could find out if beer can be brewed on the moon.
A bottle used to teach children how far litter can travel ended up on Scottish beach after 8,700-mile journey.
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