Chinese symbol for "double" has two versions: the symbol "雙" is its traditional version and the symbol "双"
is its simplified version. As you can see, its simplified version's written structure has indeed been "simplified".
The symbol "胞" means "born of the same parents". The symbol
"胎" means "embryo".
雙/双 (double) + 胞 (born of the same parents) + 胎 (embryo) = 雙胞胎/双胞胎 (twins).
Other Chinese Twins Symbols
Chinese symbol for Twin Sister
pronunciation: Luan Shen Jey May
The symbol 孿/孪 means: "twin". 孿 is the traditional version of Chinese twin symbol and 孪 is the simplified version of Chinese symbol for twin. The symbol 生 means "born". The symbol "姐" means "elder sister" and the symbol "妹" means "younger sister".