I am an only child. I've heard that only children tend to have a harder time making friends, but I'm not sure that's true.
I am not any only child because i have one sibling but I have also heard they do have a harder time with friendship. 
From my experience, it encouraged me to actively seek out friendship more, so I became more skilled at conversation and meeting new people.
Throughout history, only children were relatively uncommon but I believe that this is becoming more common now with how expensive racing kids are. 
I agree! There is also a lot of competition to throw elaborate, expensive birthday parties and buy the best things for your child. I think if you are careful it can be more affordable.
to the country.
From 1979 to 2015, the one-child policy in the People's Republic of China restricted most parents to having only one child, although it was subject to local relaxations and individual circumstances (for instance when twins were conceived).
Families may have an only child for a variety of reasons, including: personal preference, family planning, financial and emotional or physical health issues, desire to travel, stress in the family, educational advantages, late marriage, stability, focus, time constraints
an interview with Colin Petersen at the time, the group was unable to play any live gigs until they added two new members. The spectre of Colin's Bee Gees' past was making the task of recruitment even harder. "I've just auditioned my 200th applicant" he groaned. "People are assuming the new group will be a carbon copy of the Bee Gees. I must have heard "Massachusetts" 50 times. I am still looking for a good lead guitarist and a pianist to finish the line-up