How did Cher's singing voice change from the 60's to what it is today?

She used to have a higher voice, now it's a little deeper. Does anyone know what happened?How did Cher's singing voice change from the 60's to what it is today?
This really is a very good question-

but I am only going to answer this from what I have heard...as we get older- our voices change by becoming low pitched.

meaning our voices tend to get deeper and deeper as we age.

I heard this from a vocal coach. It may seem hard to believe, in fact- i still have a hard time believing it.How did Cher's singing voice change from the 60's to what it is today?
As you get older, some people lose range. However, I disagree that Cher's has changed that much since Halfbreed, Gypsies Tramps %26amp; Thieves, etc. She's always been an alto.
she never did have a singing voice in the first place so nothing to lose.