I have triplet seven-year-old cousins who don't know that I'm trans yet, mostly because I haven't exactly come out to my aunt and uncle. They live in a big house with my grandma and other uncle who I DID tell, so they probably know by now, I just haven't felt confident enough to sit down and tell them.
My cousins are always asking me why I look like a boy, why I have body hair, why I wear boxers, why I keep cutting my hair... and I just tell them it's because I like looking this way, which is true, so. Yeah. I'm going to sit down and tell them next week, and then probably tell my aunt when she gets home.

I'm going to explain that when I was born, my mom thought that I was a girl because my body looked like a girl's body. She put me in dresses and made me grow my hair long but I never liked it because it never felt right to me. Then I'll probably ask the boys how they would feel if I put them in a dress and made their hair grew long and then sent them outside to play. They'll probably say "ew, gross!" and that they wouldn't like it. I'll ask them if it would feel "right".

Now, I know I'm relying on stereotypes here, but I don't feel comfortable discussing genital dysphoria with seven-year-olds. I'm sure we can talk about it if they ever ask again when they're older.
____

It's a heck-of-a-lot easier to explain things to me niece and nephew. My niece is turning four in a month and my nephew just turned five. I pretty much caught them during playtime when I was babysitting and told them that I'm actually a boy. I kind of said something like 'my mommy THOUGHT I was a girl, but now she knows I'm a boy.' They just accepted it and asked a few innocent questions that I don't remember.

It's weird, but if i ask them "am I a girl or a boy?" they'll say boy, and they know that you use she/her pronouns for girls and he/him pronouns for boys; however, my niece corrected a little boy we were with when he used male pronouns and was like "no, she's a SHE" so it's kind of like I'm a exception to the rule, ha ha! I'll need to explain that further, and they still use my birth name more often than my chosen name, but they're getting a lot better with it, considering their dad's family and all the neighbors don't know that I'm trans.

I know I'm on the "girls" side of the fence here but I have 3 children ages 6,8, and 13.  At the time (3 years ago) my youngest two had no problems with it as they still didn't have any social interjections yet.  Now my oldest... Wow!  It broke my heart to see her have so many issues with it.  She truly could not find the right feelings for over a year.  We are an open family and we do not hide anything (trying not to fight), so she had heard many of the  comments my wife would make negatively towards me.

Enter Against Me! And the album "Transgender Dysphoria Blues".  She overheard one of the songs while I was doing my homework and asked what it was, so gee (psychology major) I turned it into a small conversation on the topic.   She asked if she could listen to the whole thing and I said sure... I mean hell, I was raised on George Carlin!  This was a turning point, and for her that album changed her perceptions of what I struggled with.  Since that day she has gone from my worst critic to my greatest ally!  She has even defended me when the Mrs. was going off on a tangent.

In the end it isn't how you tell the children more than how you handle the small conversations as they adapt well. I answer many questions to young and old...  If they want to learn, I'm willing to teach. That's how we can lose the connotations of bad publicity and move into the public light.   I'm accepted in a small conservative city in western PA, working in a home improvement store.  I believe this acceptance has come from me not being afraid to answer the questions. 

Sorry for the book...
Ali

My little sister is 13 years younger than me, so when this came up she was about 6. Our mom explained things to her, saying something like, "X looks like a girl but is really a boy inside. He's going to take medicine that will make his outside match his inside." She thinks this is the coolest thing ever. I would definitely impress upon them that this is private information, because my sister started running around school excitedly telling everyone how "her sister is going to be her brother now."