It is more accurate to say that research is inconclusive on whether same-sex parenting is any different from different-sex parenting ("Gay or straight parents, kids turn out the same" by Mr Clement Lin Yihao; Forum Online, Thursday).

Expert reviews have highlighted the limitations of studies that attempted to conclude whether same-sex parenting or different-sex parenting is better, or whether they are no different.

For example, Professor Doug Allen from Simon Fraser University in Canada recently published a study in the Marriage and Family Review, looking at same-sex parenting studies between 1995 and 2013.

I highlight three limitations that we should consider carefully.

First, some studies look at small numbers of same-sex parents because of the difficulty in identifying and recruiting people from a minority group.

Second, studies often focus on white, well-educated, and high-income same-sex parents. This is not representative of most, if not all, same-sex parents.

Thus, researchers acknowledge that these studies are only exploratory and not intended to provide a conclusive view of same-sex parenting.

Finally, researchers also note that there are differences between same-sex parents' descriptions and expert observations of their parenting activities. This is a potential issue for studies in any field, not exclusive to same-sex parenting, where humans give positively biased descriptions of themselves.

Some studies on different-sex parenting also suffer from similar limitations.

Hence, we should carefully consider a variety of social science evidence to form a balanced opinion on different-sex and same-sex parenting.

Ng Jingyang