Daughters spread cheer, sons make life dreary. That is no sweeping feminist statement, but a finding by Ulster researchers.
They quizzed 571 people aged 17 to 25 about their lives and found those who grew up with sisters were more likely to be happy and balanced.
Especially those from broken families responded saying, "Yes, having sisters helps, offering some solace."
Lead researcher Professor Tony Cassidy said: "Sisters appear to encourage more open communication and cohesion in families.
"However, brothers seemed to have the alternative effect.
"Emotional expression is fundamental to good psychological health and having sisters promotes this in families."
He said many of the participants had been brought up in families where parents had split and the impact of sisters was even more marked in these circumstances.
"I think these findings could be used by people offering support to families and children during distressing times.
"We may have to think carefully about the way we deal with families with lots of boys."
Whether the boys under stress turn out to be more introvert and/or selfish is open to question.
It is also possible when parents tend to pamper the ego of the male child, as it often happens in third world countries like India, in times of crisis the boy may tend to grapple more with his own situation than bother to reach out to the rest.