Definition
If a skill or ability is in someone's blood, it means they possess it naturally, often due to its presence within their family lineage.
天生具来（的），家学源源（的）
Music seems to be in her blood; both of her parents are musicians.
音乐似乎在她的血液里；她的父母都是音乐家。
He is good at sports; it’s clearly in his blood.
他擅长运动；这显然在他的血液里。
She has a passion for writing, perhaps it's in her blood from her grandfather who was a writer.
她对写作充满热情，也许这是她血液里从她祖父那里继承来的，他是一位作家。