China did not eliminate its one child policy because it wanted more population growth. It has in fact been relaxing it for years and did away with it entirely because of the social problems it causes:
* in traditional Chinese culture male offspring are highly valued and when allowed only one child many couples abort female fetuses. In rare but all too numerous cases newborn girls have even been killed just after birth. The result is that there are 10s of millions more men in China than women now. The one child policy has been relaxed for years to allow women to have a second child if their first was female to help balance the population. This has virtually eliminated infanticide but has been slow in re balancing population.
* measures to enforce one child policy have been very cruel, such as the common policy of denying anaesthetic to women in labour with their second child and clawback of social assistance and forced sterilisation of women without consent immediately after the birth of a child.
* the significantly greater number of young men to young women has been attributed to problems with sex crimes from human trafficking to gang rapes, though much of the evidence is anecdotal
* there are now a couple of generations of people in China raised as only children. These children have been doted upon and spoiled rotten by parents and grandparents all their lives, turning many of them into entitled "little emperors". The lack of empathy towards others and lack of respect towards elders has been unsettling to older Chinese where those traits are very important in traditional culture. It has led to institutionalisation of seniors that was almost unheard of as well as exploitation of workers and in extreme, occasional cases, incidents such as people ignoring a toddler run over by a car dying in the street while everyone goes on about their business.
Anyways population is self limiting as societies develop and direct population control has been shown to backfire. Allowing those with the means and desire to have fertility treatments to conceive is probably a net benefit to society on the whole when properly regulated. At least these parents really want to be parents and have the means and the drive to be good parents.