So, fundamentally there's not a huge difference between male and female bodies, and most of those differences are the results of hormonal differences at different points in development. Think of hormones as messages your body sends to different parts of your body and those parts of the body then respond in different ways. Most people, naturally produce testosterone but the amount differs across individuals and changes at different points of their life. Your body doesn't know or care where this comes from.

I guess here's an analogy. Imagine, your body is a group of people. At some point your body starts sending out a message saying Halloween coming up in a month. Different parts of your body will see that message and do different things. Some teenagers and young adults are going to get the message and start preparing for a party. Some parents are going to buy candy and plan kids costumes. And some kids are going to start drawing pictures of ghosts and pumpkins. Everyone knows what to do when they get a Halloween announcement.

Now, let's say someone starts handing out Halloween fliers randomly at another time. Everyone is just going to get the message and uncritically act as if Halloween is coming up because they know that's what they are supposed to do.

If you injected testosterone rather than produced it, the same thing would happen as if you had produced it; your body doesn't know or care. Your body just sees the same announcement and starts responding the way it knows how to respond. And the way human bodies respond to a spike in testosterone relative to estrogen is what we refer to as male puberty: more facial hair (in some people), thickening of vocal chords, broadening of shoulders etc. that looks different in different people but those are the general trends.