corinna's twin boys -- maarten, left, and linus -- were the first humans to be treated for their genetic disorder while still inside the womb.
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letter exposes 22 lab animal deaths at uc berkeley from 2015 to 2017
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twins linus, left, and maarten have more sweat glands and tooth precursors than their older brother joshua, 5, after being treated with a drug in utero.
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"we were quite surprised to find there were no significant differences," says study author
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