One of the replies referred to this study from 1991.
https://www.jaacap.org/article/S0890-8567(10)60067-6/pdf
The link takes you to the whole paper, but here is the abstract.
'Mothers of Boys with Gender Identity Disorder:
A Comparison of Matched Controls
SONIA MARANTZ, PH.D., AND SUSAN COATES, PH.D.
Abstract. This pilot study compared mothers of boys with gender identity disorder (GID) with mothers of
normal boys to determine whether differences in psychopathology and child-rearing attitudes and practices could
be identified. Results of the Diagnostic Interview for Borderlines and the Beck Depression Inventory revealed that
mothers of boys with GID had more symptoms of depression and more often met the criteria for Borderline
Personality Disorder than the controls. Fifty-three percent of the mothers of boys with GID compared with only
6% of controls met the diagnosis for Borderline Personality Disorder on the Diagnostic Interview for Borderlines
or had symptoms of depression on the Beck Depression Inventory. Results of the Summers and Walsh Symbiosis
Scale suggested that mothers of probands had child-rearing attitudes and practices that encouraged symbiosis and
discouraged the development of autonomy. J . Am. Acad. Child Adolesc. Psychiatry, 1991, 30, 2:310-315. Key
Words: gender identity disorder, maternal psychopathology, Beck Depression Inventory, Diagnostic Interview for
Borderlines, symbiosis, autonomy, child-rearing practices.'