Basically Ian and Cindy were together, but she was having an affair with Simon Wicks (Sharon's man), and Ian thought that the kid (Steven) was his, but it wasn't.
Then Ian and Cindy get back together a few years later and that's when Lucy & Peter were born.
So Steven is technically their half-brother, but he's not related to Ian.
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Ian found out that Steven was writing people hate mail (
) and they have an argument and he tells Steven that he's not his real father. That's when Steven decides to go to New Zealand to find his real dad (Simon). (In 2002)
Then Steven came back in 2007 and starts stalking Ian, he pretends to be the dead wife Cindy and lures Ian to an empty flat and takes him prisoner. He then goes to meet up with Jane and tries to kiss her
Lucy follows him to the flat and finds Ian tied up prisoner, she escapes and tells Jane. Steven is upset and tries to shoot himself, but Jane bursts in and tries to stop him, the gun accidentally goes off and shoots her in the stomach. That's why she can't have kids.
Then he got admitted to a psychiatric hospital, when he came out he tried to kill himself again by covering himself in petrol, but Stacey Slater stopped him.
He then falls in love with Stacey and tries to lose his virginity to her
Christian finds out that he's a virgin and couldn't get it up for Stacey and they have an argument, then Steven kisses him.
Steven goes into denial and ends up banging Stacey. But she dumps him after she finds out he's gay.
Then Steven tries it on with Christian but he rejects him. Then he finally comes out as gay.
Then Steven was jealous of Lucy getting all the attention, so he made plans to take her to France. Pat finds out and tries to stop him but gets ran over. Steven tries to murder Pat in hospital with a pillow so she won't tell anyone about his plan to get rid of Lucy, until Ian stops him.
Then Ian told him to leave forever, so he did.
Now he's back.
Such a mess.
Eastenders always bringing the mess.
--
It's so obvious there's going to be a Johnny/Lauren/Steven/Ben love square in the future though.
Lucy was lowkey my fave too so. 
i wonder why Peter didn't come back w Lauren
I can never keep up with all these sprogs.