Childhood 'is' (ja tutaj dodalabym, ze to 'ma byc' ale de facto nie zawsze jest...mozna ..is supposed to be) a part of life connected with our best memories . Although 'kids' (nie lubie tego slowa, tutaj 'children') and later 'adult people' ADULTS who grew up without A sibling have rather different memories 'and' (zle slowo tutaj, miales na mysli napisac THAN sometimes 'characters' (slowo calkowicie nie pasuje-poszukaj inne) than people with siblingS. The main reason 'of' FOR these differences is THE upbringing of children by parents. As everything in our 'live' (tutaj masz czasownik, a miales na mysli rzeczownik LIFE) it has as many 'cons as pros' (ja woler advantagesd and disadvantages) ,
At first AN only child has usually more toys, clothes and generally 'stuff' (a co to jest ten 'stuff' at best, kolokw) than other children, because maintenance of one 'kid' CHILD is much more cheaper than two or three. The other thing is THE fact that it is very common that parents treat AN only child as a gift 'of' FROM God and they 'are spending' SPEND 'with child more time' (zla kol slow...more time with one child) than parents with several children.
In spite of these positive aspects upbringing of AN only child has some 'dark' (lepsze slowo byloby 'hidden') sides. These 'kids' CHILDREN are often spoiled . They have everything for themselves and they 'can't' (zle slowo tutaj, co miales na mysli, to jest to, ze one nie sa nauczone-popraw) TO share with other CHILDREN. That is why they are sometimes not liked by 'thier' (ortog) colleagues especially at 'the beginning' (zmien to...at the time when they begin their) 'of' (niepotr) education . THE second minus of being an only child is THE fact that most parents have much more higher expectations 'to' OF these children . They want them to learn better, behave 'good' (zle slowo, at best kolokw- BETTER) . When AN only child is A teenager he 'can't'(zmien slowo) have fun 'on' (kalka z polskiego 'na' w ang., AT) parties as often as his mates because parents are worried about him.(no i co z tego- tutaj musisz dokonczyc, ze oni oczekuje jego w domu wczesniej)
Summarizing, contrary to 'apperance' (ortog i tutaj w l. mnogiej) being an only child 'has except' (po jakiemu to? zla kol slow - except having) many good things, also HAS some bad sides . Parents should find a right balance (tutaj cos brakuje, jaki balance?) in THE upbringing of children.