blood will tell
One will inevitably display the unfavorable qualities of one's relatives. Of course Mark never has any money, just like his parents. Blood will tell, after all.
Blood will tell.
Prov. A person whose ancestors had certain characteristics, often bad ones, will eventually turn out to be similar. Lisa's father was a gambler, and now Lisa has started to gamble, too. Blood will tell. William went to all the best schools, but he's just as vulgar as the rest of his family. Blood will tell.
blood will tell
family characteristics cannot be concealed. proverb