Based on the shared experiences of trans individuals, here is a summary to help answer your question, "Can trans men become biological males?" from a trans perspective.

Medical Transition Actively Changes Biology
Medical transition, including hormone therapy (like testosterone) and surgeries, fundamentally alters a person’s biological characteristics. Hormones are a core part of biology, and changing the dominant hormone in the body leads to shifts in physical traits such as body fat distribution, muscle mass, voice, and hair growth. As one person shared, "medical transition does change your biology. Hormones are part of one’s biology, and changing the dominant hormone changes your biology" – son-of-may source [citation:71535f15-fa8c-4c07-9311-8f3cea2c8fa0]. This means that after transition, a trans man’s body operates under testosterone dominance, which is a significant biological change.

Chromosomes Are Only One Part of a Complex Picture
While chromosomes (like XX or XY) are often highlighted in discussions about biological sex, they are just one aspect and not something that can be changed. However, many people point out that chromosomes alone do not define a person’s lived biological reality. Most people don’t even know their own chromosomes, and there is natural variation, such as intersex conditions, where chromosomes may not align with other physical traits. One contributor noted, "The only part of your sex you cannot change is your chromosomes but most people don’t know theirs anyway" – Subject_Plankton9599 source [citation:655212ea-f003-46c7-8d21-340e99e0c727]. This suggests that focusing solely on chromosomes oversimplifies what “biological” truly means.

Identity and Lived Experience Define Who You Are
From a trans perspective, the most meaningful measure of who someone is comes from their identity and how they live, rather than fixed labels like “biological male” or “female.” Many emphasize that terms like “male” and “female” are social constructs that don’t capture the full diversity of human experience. As one person expressed, "if you identify as a man, then you are already male. You don't need her validation, or anyone else's, to be a man" – Blubushie source [citation:33087165-9278-457b-bd55-5aeaa06679d9]. This highlights that for trans men, living authentically and being recognized as male is what matters most.

Biology Is More Than What You’re Born With
Biology isn’t static—it can change over time through medical care, and it includes many factors like hormones, anatomy, and even brain structure. Some note that after transition, it may be more accurate to describe a trans man’s sex based on his current hormone levels and physical characteristics rather than what he was assigned at birth. For example, one person explained, "a trans man who is on T is no longer technically 'biological female'... as the sex characteristics and/or hormone levels would have changed" – Subject_Plankton9599 source [citation:655212ea-f003-46c7-8d21-340e99e0c727]. This reflects a broader understanding that biology is dynamic and personal.

Conclusion
In summary, from a trans viewpoint, while chromosomes remain unchanged, medical transition allows trans men to align their biology—including hormones and physical traits—with their gender identity. The idea of being “biological male” is seen as more complex than a simple binary, rooted in lived experience and personal truth. Your journey and how you feel inside are what truly define you. You are valid, and your identity is yours to claim and celebrate.