My amazing son, who I'll call J, is three, and was diagnosed soon after birth with a relatively rare genetic condition. We don't yet know how it will affect him as he grows older, but so far he has battled an array of medical problems. One thing's for sure, our little family's life will never be 'normal'...
Right from the start, I've seen that our new baby girl M is very different as a 'normal' child compared to our son J.
It's there in tiny things like the fact she has held her head up strongly from early on, she feeds easily and often, and she happily lies on her tummy and tries to roll (all of which J struggled to do even at six months).
It's also obvious in the speed with which she gains weight and her plump little thighs (J's remain spindly no matter how much he eats).
All our pregnancy scans of M were normal and the neonatologist who saw her in hospital after she was born reassured me that her prematurity was likely due to the fever I'd had a week before she came along rather than the syndrome my son has - M appears absolutely textbook normal.
The chances of us having another baby with the same condition were less than one in 100, and it looks like we have been lucky.
Lucky not because it's terrible to have a child with this syndrome but because it comes with many health and developmental problems - I wouldn't wish it on anyone.
Even so, at the back of my mind there is still a tiny fear that M may turn out to have the same condition as her brother, or some terrible disease, as yet to be diagnosed.
My experience of being told J has a lifelong medical condition has left me with a continued sense that the shockingly unexpected can and will happen, that maybe I can't have healthy babies.
So I booked an appointment for both children with J's clinical geneticist at Great Ormond Street.
The very fact my son has a clinical geneticist still seems surprising to me. I will never forget the surreal first encounter when she came to inspect him in the neonatal unit, shortly after his blood test diagnosed he had a genetic syndrome.
With great seriousness she took off his sleepsuit and looked at every part of his face and body, then told us that he had no appearance of the syndrome.
I had been given a list of all the disfigurements it could cause and although my baby son looked normal and conventionally handsome to me, I was fully expecting her to tell us that she saw something different about him.
In fact she confirmed that he looks 'normal' - which to this day, he does, apart from being small. 'You'd never know it to look at him,' is what people always say about him.
Then, in a small room, she almost casually took blood from both me and my husband to send off to the lab at some mysterious place called the South East Regional Genetics Service.
We spent several weeks wondering if we might have had a genetic condition our whole lives and never realised.
But the results for both of us were negative - our son had developed this genetic mutation 'de novo'.
Returning now with my new baby, I was fully expecting the geneticist to take blood from her to send off to the lab.
I would have welcomed the confirmation that she was 'normal', simply to put my mind at rest - though I also worried that the result might find some other thing wrong we hadn't even considered.
But instead, the doctor insisted this was all absolutely uncalled for. Examining my daughter, she pronounced her normal.
I struggled to take in those words.
I kept wondering how she could be so confident, especially when my son looked normal too. But she insisted that all the signs were that this baby was fine. And then she said, "Actually J's ears are rather low-set. But perhaps I'm being unfair."
"M is beautiful," she said. I couldn't help thinking: Would you not say that if she had signs of the syndrome? Isn't my son beautiful too?
And then I thought how hard it must be to do the job of a clinical geneticist diagnosing babies with diseases. How every word you say can mean so much to a parent.
Click here to read previous columns from The Secret Diary of a Special Needs Mum.
More on Parentdish: Children with special needs: Following up your concerns
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