144 isn't bad for a study like this, people publish studies with much smaller sample sizes I think there are legitimate reasons for restricting the sample on t

144 isn't bad for a study like this, people publish studies with much smaller sample sizes I think there are legitimate reasons for restricting the sample on the basis of race/ethnicity and sexual orientation. It is plausible that both are confounding variables (even if there is no biological difference in the psychology of sexual attraction in those cases, there are no doubt differences in cultural influences); but, to properly control for them, you need adequate representation of minorities in your sample, which may mean your sample needs to be a lot bigger, which makes your study take longer and cost more, and you might not have that in your time and money budget. Another approach is to try to oversample minorities, but that brings its own statistical risks. So, the idea of limiting your study to cisheterosexual people from the ethnoracial majority, and then potentially following up with future studies specifically targeting LGBT and ethnoracially diverse populations, could be a reasonable approach 18–27 is likely because it is easy for researchers based at universities to use students, most of whom are relatively young (and mature age students are not just fewer, they are possibly even less representative of the average person of their age)