We only have one ds, and I know that if I had another, I would love them the same, but not necessarily like them the same. But to be honest, having one ds is wonderful. Life is so much easier than some of my friends who have 2 or more. It depends on the personality of your child now. DS has always been self contained.
However, I know what it is like to be the lesser favoured child. My mother has always had one favourite - my older brother. None of the other children come close. So yes, it is possible to have just one favourite and love one more than another.
As a child it was awful to see that he got music lessons, martial arts classes, new Nike trainers, expensive equipment. The rest of us got nothing - my mother 'invested' solely in her eldest son. My sister and I were girls and didn't count - we were simply expected to marry well. Younger brother suffered the most - he was by far the most neglected.
When I saw my older brother had all these privileges, I was disappointed when it was my turn. I wasn't allowed piano lessons or dance lessons. When I asked for a camera for a photography course, I wasn't allowed one. A year later, my older brother suddenly thought photography was a good idea - he got a new camera (top of the range no less) and a photography course courtesy of mother.
When my older brother studied medicine, my younger brother wasn't allowed to as they could only afford for one child to do medicine (this is overseas). It caused no end of emotional damage to my younger brother who ended up dropping out of university altogether as he hated his course.
When older brother got married, she got involved in the wedding details. When sister and I got married - we were given some money, but no help - we organised everything ourselves. Ironically -we both married where mother lived, whilst living hours away - still she was no help.
Older brother has now moved to Canada - and mother will go and spend 6 months of the year with him - to help with his 4 kids. Believe it or not, I have not seen my mother for three years or even my brother for 5 years.
She calls her eldest twice a week when not with him. My sister and I get a call maybe two or three times a year (birthday or christmas) Youngest brother, lives with her still, but he is considered 'the burden'. Whilst she remembers all my brother's children's birthdays, she has never remembered ds birthday or hasn't ever sent a present for birthday or christmas - and for the first three years, she had to be kept reminded what ds' name was.
I know it sounds like the worst dysfunctional family dynamics, but I do get on with mother and my brother. I just accept her for what she is. When you tell her, she just can't see it. She says she loves all of us but that her eldest 'needs' her more.
My other siblings and I just laugh about how now - almost 40 years later, she still favours him and clearly loves him more. Thankfully I do not need my mother or I would have gone crazy. Last time she visited me(three years ago), it was supposed to be for three months, she asked to change her ticket after two weeks as she was so bored. She stayed three weeks.
PS: sorry this turned out longer than I thought it would)