Noticed that 3 week old baby has a mild y-shaped bum crack and a very small pink-reddish birth mark out 2 inches above his bum. dr never mentioned anything. is this likely spina bifida occulta?

Spina bifida: With an unusual buttock cleaveage and combined with what sounds like a a skin hemangioma it would be worthwhile to have the local MD order an ultrasound as that is an easy noninvasive way to sort out this issue in a baby this age.

Not necessarily: The rose colored birthmark is likely the same as many have at the base of the neck called a stork's bite. I see them occasionally from the gluteal cleft to the top of the head but usually in the mid-line. The Y shaped cleft is a common variation and rarely associated with a tethered cord (anchored) which would become evident much later but not spina bifida.