Musical siblings and harmonies

[Hassled]

I was listening to the wondrous Everly Brothers which took me (as most things seem to) to the Beach Boys, and I was thinking about something I read about how siblings/cousins can harmonise so perfectly because they've grown up with the same speech patterns/intonations and have very similar voices. Is this true? Who else is there?

can't remember the name now, those brothers who sing "staying alive"

BeeGees

Of course - the Bee Gees. Forgot about them, but a prime example.

If my brother and I were to start harmonising people's ears would start bleeding.

thanks dunno why the name slipped my mind. Were the Carpenters siblings? No idea if about the theory though hassled.

yes Carpenters too

so why arent Same Difference in this category then?

Nolans

Jacksons

Yes, Carpenters were siblings. And yes, they were good at harmonising. Same Difference should be good going by the shared gene pool logic .

I might have to YouTube the Nolans now - not something I ever thought I'd do .

Ooh yes, the Jacksons. Top example. They sounded good together because their voices are so similar.

Osmonds