In one survey, 50% of transwomen who tucked were concerned about negative health effects.
A survey  of transwomen who tucked (the process of reducing the visible male crotch bulge) reported that half were concerned about the health effects of tucking.
Their reported symptoms included itching (28%), rash (21%), testicular pain (17%), penile pain (14%), and skin infections (12%).
In addition, patients may be reluctant to seek medical care for testicular complaints and when they do, it may be already late to salvage the testis. 
 Poteat, T., Malik, M., & Cooney, E. (2018). Understanding the health effects of binding and tucking for gender affirmation. Journal of Clinical and Translational Science 2 (Suppl 1), 76. [Link]
 Debarbo, C.J.M. (2020). Rare cause of testicular torsion in a transwoman: A case report. Urology Case Reports 33. [Link]