Is it true that most brothers with sisters make great boyfriends/husbands?

Im not saying it's a bad thing. Both my brothers have ladies abd they treat them so good even though they mess up at times. My oldest bro is a great husband and my second bro is so good to his wife too.
I have a cousin that doesn't have sisters but he is a wonderful husband and father.

My best friend told me, "I do anything to have brothers like yours. You are so lucky. My brothers just laugh at me or don't care when I'm upset."