In one’s blood:
If an ability or skill is in someone’s blood, they have it naturally, usually because it already exists in their family.
“To have something in someone’s blood” 或 “be in someone’s blood” 的意思是 “某人的能力、天分或特质是遗传的”，也就是俗话说的 “天生的”。比如，一家人当中如果有许多成员都从事一类工作或具备同一种天分，那就可以说这项技能是他们家族遗传的，即 “in their blood”。
例句
Being a baker is in my blood – our family has owned a bakery for many generations.
我骨子里就是个糕点师。我们家经营面包房已经好几代了。
Art is in my blood – my mother was a painter and her father was a sculptor.
我的艺术细胞是与生俱来的。我母亲曾是一名画家，她父亲曾是一名雕塑家。
People in every generation of Pete’s family have been football players – it’s in their blood.
彼得家的每一代人都是足球运动员。他们天生就是这块料。
