two identical and one fraternal triplet
Mixed Triplets
Meaning — Mixed triplets are triplets in which two babies are identical and the third is fraternal. One way this can happen is when two eggs are fertilized and one of those fertilized eggs later splits into two embryos. The split pair is identical; the baby from the other fertilized egg is fraternal to them.
Why now
A California couple welcomed two identical boys and one fraternal boy on August 18, 2026. CBS Los Angeles reported that each baby weighed more than six pounds, for a combined 19.3 pounds.
More context
Context
What does “heavy mixed triplets California birth” mean?
That search phrase combines two reasons the story stood out:
- The babies were mixed triplets — two identical boys and one fraternal boy.
- Their combined birth weight was 19.3 pounds, which drew attention because it was close to the reported record for the heaviest living triplets at birth.
“Heavy” is not a medical type of triplet. It is part of the news and search context about their unusually high combined birth weight.
Identical vs. fraternal vs. mixed triplets
- Identical triplets: one fertilized egg splits into three embryos.
- Fraternal triplets: three separately fertilized eggs develop into three babies.
- Mixed triplets: two babies are identical and one is fraternal.
Evidence
Sources
- Triplets — Cleveland Clinic
Supports the definitions of identical, fraternal and mixed triplets and how mixed triplets can form.
- Multiple births — Cleveland Clinic
Supports the medical background for how multiple pregnancies and triplet types form.
- South Los Angeles couple welcomes 19-pound triplets — CBS Los Angeles
Supports the California event, the babies' mixed-triplet relationship and their combined 19.3-pound birth weight.
- Rare mixed triplets near birth-weight record — People
Supports the reported near-record context for the combined birth weight.