@elloello,
elloello, do any believers in Islam question such statements as those you are making? What is "doing justice" to a woman? Unmarried women do not necessarily become prostitutes...that is an illogical and unjustified assertion. There are more men born in this world than women, so why do we end up with fewer men? War and tribal conflict? Let's work to solve that...rather than justify a man having four wives.
The purpose of creation is that beings will create children. Well, yes. If we don't, our tribe will not survive. But haven't we evolved beyond that? People who have created reading and writing, music, libraries and schools, art and museums...there is more reason to stay alive than just to procreate, which some of must do -- you are right there.
Males and females cannot be seen as at opposite poles, except in extreme cases ( we all know a super feminine woman and a hugely macho man,) and there is surely a range in the middle where most of us fall...some with more or less leanings toward one pole or the other. There are many ways to nurture children without having borne them...the world needs nurturers and caretakers as much as it needs those who can do the nine-month thing. Studies show that animals indulge in and enjoy same-sex stimulation...perhaps this helps in bonding or to strengthen the tribe.