In one of Venom's endings, he meets an orphan child named Eddie. He adopts Eddie and takes Eddie with him. On the wiki it says that Eddie is a boy, but they(I don't know what word to use)look like a girl. So is the kid a boy or a girl?
Here's what essentially happened, Venom after killing Millia realises that nothing can be accomplished in an Organization of sorrow and death (and that it took TWO deaths for him to realize this), so he disbands the Assassins' Organization:
Millia: "How...Unfortunate...So this is...the end..."
Venom: "Rest in peace, Millia. I think...that he is waiting for you too. (It's over...But what is this emptiness I feel?)"
Venom: "This is...the usual dream, huh?"
Nightmare Zato: "rrRhhhmmm..."
Venom: "Disappear. I no longer fear Nightmares!"
Nightmare Zato: "rrrrhhhhhaaaAAAAAHhhhh..."
Venom: "You still fight...Fine. I will destroy this illusion, and with it, MY FEELINGS FOR MASTER ZATO!"
Assassin Servant: "Are you awake, sir?"
Venom: "Yes. I feel really good this morning."
Assassin Servant: "Is that so?"
Venom: "Gather everyone. Inform them that, as of today, the Assassins' Organization is disbanded."
Assassin Servant: "Wha-! That's...why?"
Venom: "Nothing can be done when one is tied down by an Organization. How ironic. It took two deaths for me to realize that..."
Venom: "What's wrong? What are you doing there?"
Boy: "The town was...burned down."
Venom: "I see...What happened to your family?"
Venom: "You have no one to go to?"
Venom: "...Do you want to come with me?"
Venom: "This long journey was starting to feel a little lonely. I figure I could use a companion."
Boy: "Mister...what do you do for a living?"
Venom: "Me? I'm a hustler. I never stay in one place though."
Venom: "I shoot pool. You know what that is?"
Venom: "I'll teach you. Eventually. Come with me. There's someone in the town up ahead who's waiting for a match."
Boy: "Okay. Um...is it really okay to come with you?"
Venom: "Only if you want to. My name is Venom. What's yours?"
Venom: "...That's a good name. Let's get going."
It seems that this young boy was caught up in a recent post-Crusades conflict and the sole survivor of a destroyed village, much like how Millia, Zato, and Venom were orphaned during the Crusades.
It's unclear exactly when this might have taken place, but as of 2182 the Organization is still in existence based on the Novel Butterfly and Her Gale, so in all probability it has an extremely low chance of being canonical, so at best it's an alternate ending.
And yes, it's pretty clear he's a boy (based on the voice acting), but he just so happens to have long hair so it could be misleading.
And no, contrary to fan belief he is no relation to Bridget, since it appears he's the survivor of a destroyed village and not a relative or Bridget's twin brother.
But, that doesn't necessarily mean that Venom won't meet up with Eddie in the future, should Venom retire. Based on what we know of Gaiden, it's very possible, though the circumstances may be different.