Though there's a strong resemblance in the wide, expressive mouth and the tendency to do well on network sitcoms, there's no relation between the once and future child stars.

Despite their similar looks, there's actually a 16-year age gap between them. It's hard to believe, but Mayim Bialik will turn 40 in December.

However, there are also a lot of other similarities. Both were born in southern California -- Sher in Los Angeles, Bialik in San Diego -- both have birthdays in December and both started acting when they were in their early teens.

If you want to go even deeper into the meaningless coincidences, both got their big TV breaks with eight-episode runs on sitcoms starting with the letter W. Sher first came to people's attention as Gretchen in a short run on Showtime's "Weeds," while Bialik first turned heads in the final 1988-89 season of the sitcom "Webster."

Bialik was a little younger than Sher when she scored her first series-regular role. She debuted in the title role on the hit '90s sitcom "Blossom" when she was 14 -- incidentally, this was more than a year before Sher was even born. Sher, on the other hand, wasn't cast in "The Middle," her first series-regular role, until she was 17.

It remains to be seen if Sher will have an easier ride after her child-star gig ends. Bialik mostly (though not entirely) disappeared from the screen in the 15 years after "Blossom" ended.

Though, to be fair, she was busy in those years getting a PhD in neuroscience, which proved to be good preparation for her "Big Bang Theory" role as ... a neuroscientist.

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