"龍鳳胎"英文是什麼?

龍鳳胎 = twins of different / opposite sexes
由於見到有一大段英文，惟恐有所誤會，故此簡略譯一譯：
Fraternal twins (commonly known as "non-identi cal twins") usually occur when two fertilized eggs are implanted in the uterine wall at the same time. The two eggs form two zygotes, and these twins are therefore also known as dizygotic as well as biovular twins. When two eggs are independently fertilized by two different sperm cells, fraternal twins result.

Dizygotic twins, like any other siblings, have an extremely small chance of having the exact same chromosome profile. Like any other siblings, fraternal twins may look very similar, particularly given that they are the same age. However, fraternal twins may also look very different from each other. They may be different sexes or the same sex. The same holds true for brothers and sisters from the same parents, meaning that fraternal twins are simply brothers and/or sisters who happen to have the same age.
異卵孿生子發生，通常是因為兩個受精卵同時於子宮壁著床。兩個受精卵形成兩個胚胎，這些雙胞胎因此亦稱為dizygotic及biovular twins。當兩個卵子各自接受一個精子受精，便形成異卵孿生子。
異卵孿生子跟普通兄弟姊妹的情況一樣，彼此間擁有完全吻合的基因組合的機會極微。如普通兄弟姊妹般，異卵孿生子可能長相很相似，尤其是因為他們年齡相同。不過，異卵孿生子也可以長得很不一樣，他們概可以同一性別，也可以不同，就如同一對父母所生的子女般，即是異卵孿生子根本上是同一年齡的兄弟姊妹而已。
以上根本冇講到Fraternal twins＝龍鳳胎，只係講Fraternal twins可以係龍鳳胎。wikipedia原文仲有總共有五種雙胞胎，其中只有Fraternal twins先有可能係不同性別。如果因為咁而產生日常生活中以Fraternal twins＝龍鳳胎係有可能，但twins of different / opposite sexes肯定一聽就明。另一個叫法係 a pigeon pair。

龍鳳胎 = Fraternal twins 或 non-identical twins

Fraternal twins (commonly known as "non-identical twins") usually occur when two fertilized eggs are implanted in the uterine wall at the same time. The two eggs form two zygotes, and these twins are therefore also known as dizygotic as well as biovular twins. When two eggs are independently fertilized by two different sperm cells, fraternal twins result.

Dizygotic twins, like any other siblings, have an extremely small chance of having the exact same chromosome profile. Like any other siblings, fraternal twins may look very similar, particularly given that they are the same age. However, fraternal twins may also look very different from each other. They may be different sexes or the same sex. The same holds true for brothers and sisters from the same parents, meaning that fraternal twins are simply brothers and/or sisters who happen to have the same age.

twins of different sex
(non-identical twins may be of the same sex)

non-identical twins(正式名字:異卵雙胎)

Twins