You can't fight blood — family traits (looks, temper, tendencies) are often unavoidable; like father, like son.
あの頑固さは父親譲りだね。血は争えないと言うけど本当にそうだ。
That stubbornness comes from his father. They say you can't fight blood, and it's really true.
音楽の才能があるのは偶然かと思ったが、母も同じように音楽的だった。血は争えないね。
I thought musical talent was a coincidence, but my mother was musical too. You can't fight blood.
兄弟は性格が似ていることが多い。血は争えないという表現がぴったりだ。
Siblings often have similar personalities. The phrase 'you can't fight blood' fits perfectly.