For as long as I have known my friend Felicity, she has been rather shy. But as soon as her son Christian, now six, was born, she underwent a personality transplant.
No more the shrinking violet. These days a more fitting description is 'kick-ass mum."
I marvel at how Felicity takes no prisoners in making her feelings known, standing up for Christian at every opportunity and leaving no room for any doubt that, if you upset her son, she will have something to say about it.
She regularly calls Christian's headteacher to discuss any misgivings with her about homework or how he has fared in class that day.
Far from considering she may be a thorn in the school's side, Felicity is confident she is doing the right thing for her son. In restaurants she berates other diners for swearing around her son's innocent ears and out and about, she challenges gangs for their rowdy behaviour.
"There's no doubt my maternal protectiveness kicks in," says Felicity.
"Seeing such behaviour around Christian makes my blood boil. I'm not going to stand back and let it happen. I consider it my job to stand up for my son.
"My mum is no longer with us but she did the same for me. If more parents were like it, the world would be a more pleasant place to be."
I admire Felicity's approach, while I'm not blessed with the same level of chutzpah, there have been times when I have surprised myself – opening my mouth to tell someone in a position of authority that I disagree with or object to something they are saying, on my daughters' behalf.
It's not fair to say this is a complete turnaround for me as I have always relished standing up for what I think is right, but bring protecting my girls into the equation and things take on a new dimension of certainty.
"Blimey, you're a mum, hear you roar," my friend Sian remarked once after a bizarre confrontation with an over strict dancing teacher.
But a mother's instinct – and willingness to put herself in a metaphorical firing line for their children can also have more serious overtones.
My friend Katie went against medical staff's wishes and took her baby son out of hospital when he was at risk of jaundice.
Looking back, she finds it hard to believe she told doctors that as his mum, she knew best - and she was proved right.
"It was like an out of body experience," says Katie. "I was only 21 when I had Alex and it's fair to say I wasn't the most confident of people, but literally days after he was born I felt like I had to fight for his best interests, so I did.
"Doctors were telling me he needed to be in hospital but I just couldn't see why and knew being at home would be better for him. He improved and thrived very quickly after that."
So can it go too far? Can mums become over confident or protective?
My own mum is a fantastic role model of someone who has always stood up for her children. But now she says she cringes when she thinks of how she 'stormed' into situations when she could have taken a moment to step back and think.
I remember her arguing with people on beaches, in shops and even a theatre, when they suggested me and my brother should be seen and not heard. These days, she's embarrassed about how she possibly over-reacted.
Susan Grossman is a life coach who works with mums. "It is perfectly natural to be protective," she says.
"Mothers instinctively, like all animals, want to protect their offspring. As a coach I have worked with new mums who won't let visitors ring the doorbell for fear of 'waking the baby'. How will the child get to learn to live with noise? Over protectiveness can impact on a baby's development."
But of course there is another side of the coin.
For every 'over confident' mother, there's another who's struggling to find their feet.
Susan says: "Many women I coach, want to go back to work but are tortured by feelings of guilt. They lack confidence and say they are out of touch. I reassure them that a skill is a skill; it doesn't matter when you gained it. A baby doesn't negate everything that came before it.
"It's okay to put yourself first sometimes. You may need help to be reminded of who you were before the baby came along, your skills and what you achieved, and most importantly what you want to do with the rest of your life - apart from being a mum."