Final answer:
The Traditional masculinity-femininity model has received the least support, as research supports more nuanced models, acknowledging individual differences in gender expression and identity.
Step-by-step explanation:
The model for the relationship between gender type and psychological adjustment that has received the least support from research is the Traditional masculinity-femininity model. This model posits a binary view of gender with distinct roles for males and females, which has been increasingly challenged by evidence of more fluid and cooperative gender expressions, as well as the understanding that individuals may not fit neatly into these binary categories. Research into gender identity, particularly related to the experience of transgender and gender-nonconforming youth, has demonstrated the need for more nuanced models of gender that acknowledge variability and support individual differences in gender expression and identity.