Run in the family:
If a quality, ability, disease, etc. runs in the family, many members of the family have it.
“Run in the family” 的意思是 “家庭中的许多成员都具备相同的特征、能力或患有同一种疾病”，也就是人们常说的 “世代相传，家族遗传”。这个表达既可以用来谈论好事，也可以谈论坏事。
例句
My friend had twins for a second time. They run in her family, but she was still surprised when she found out.
我朋友生了第二对双胞胎。虽然生双胞胎是她家族遗传的，但当她得知要再生一对双胞胎时，还是很吃惊。
High blood pressure runs in the family, so I always get it checked once a year by the doctor.
高血压是我们家族遗传的，所以我每年都去医生那里检查一次。
Lots of people in my family are teachers. It definitely runs in the family!
我家里很多人都是教师。这肯定是家族遗传！
