种族混合

例句：

1. 1. The city has seen a significant increase in the number of mixed-race families over the past decade.
   过去十年，这个城市混合种族的家庭数量显著增加。
2. 2. The researcher found that genetic mixing among different races is a natural occurrence.
   研究者发现，不同种族之间的基因混合是一种自然现象。
3. 3. The children were raised in a household where race mixing was encouraged.
   这些孩子在一个鼓励混血的家庭中长大。