But while the Spice Girl and husband Stephen are over the moon to welcome Mel's third daughter - and their first child together – into the world, it's sad some people attempt to spoil this happy news.
One national newspaper suspended comments on its website, after a flurry of statements similar to this one from an anonymous writer: "Some women seem to be only capable of birthing girls. Like Jessica Alba, Jennifer Garner, Matt Damon's wife, and now, Mel B. The reality is, only a boy will carry the family's surname which no number of baby girls can do. I bet their spouses are secretly disappointed... well, keep trying."
Having a healthy child should always be a celebration. But when you've already got one or more of the same gender, why do some people have to make negative comments?
It's not just parents of girls who feel it. When my eldest son was just a baby, I was chatting to a shop assistant who admired his cherubic smile.
She asked if I would be having any more, and I confided that I wasn't sure. In those early months, I was shocked at how much work a baby could be.
"Anyway," I quipped. "I've already got Little Mr Perfect."
"But you must want Little Miss Perfect," she said.
Her point being that if I ever did try again, it would be to complete the set and have a girl. Not because I wanted another child.
Two years later and I was pregnant again. My 20-week scan revealed it was a boy.
Oh never mind, better luck next time," said a mum at my local toddler group.
I was aghast. Having had two miscarriages before starting my family, I was just glad to have a healthy baby growing inside me.
As my husband and I have a prevalence of boys in our family, we'd predicted another son.
But I can't deny I'd been expecting that sort of reaction. That was why I wanted to know the gender second time around.
With no plans to have more than two, we didn't want any disappointed faces when another little boy arrived.
My friend Amanda recently had her third son, and enjoyed many messages from well-wishers in the hospital.
But she told me: "One family friend sent me a note saying 'Now you've got him, I'm sure you wouldn't swap him for the world - not even for a girl'.
"It was put in a subtle way. But she was still implying I'd settled for second best."
Three years ago, Jenni, 39, started up an online forum for parents of all-boy families.
With three sons, now aged eight, five and three, she got fed up of the negative comments from strangers and friends alike.
She says: "When I was pregnant the second time, I got a lot of comments from friends who had the pigeon pair 'wishing' that I'd have their 'luck' and have one of each too.
"Hubby is the fifth of six boys, and I am the youngest of three girls, so it made sense for us to have a same-gender family.
"When the scan revealed our third child was a boy, I immediately sent a message to all our family and friends saying 'Proud to announce that we are adding another boy to our family. Want to tell everyone now so that he receives only positive responses at birth!'"
Apart from the obvious sharing of clothes, toys and movies, Jenni has noticed definite benefits to having children of the same gender.
"Despite the innate differences in their personalities, my boys adore each other and really look out for one another.
"Many of our friends who have the pigeon pair are starting to notice and admit that as their children get older, they have less in common, and lack that 'bond' that same gender siblings have."
Mum of five girls Jodi agrees there are definite benefits. "We can all talk freely about gender specific issues without fear of ridicule or embarrassment. Shaving, periods, bras and tampons are all common conversation topics in our home.
"And don't feel sorry for Dad, he loves giving his input - as misguided as that may be sometimes!
"But whenever I was pregnant, everyone just assumed I wanted a boy this time.
"The more I protested, the more convinced they were that I was just protecting myself from the inevitable disappointment I was obviously going to feel if I had another girl.
"My girls are gorgeous... how could I possibly be disappointed?"
I'm sure Mel B feels the same.
And with so many couples struggling to have children in the first place, why should we ridicule those who do have happy, healthy offspring?
Do you have all girls or all boys? Do people make comments?