I have a OLTL question?!

I have a OLTL question?

I have only been watching OLTL a short time. I starting watching it on Soapnet. So, I'm a little confused about how Jessica and Natalie are sisters but only Jessica is a Lawrence and Clint isn't their father and Roxie is Natalies mother. Help me out please I"m passed confused

Natalie, who was working with Allison Perkins, explained that she had been born to Viki and Clint and that she had been the baby kidnapped-but Jessica was the one returned. Jessica was, in fact, the daughter of Roxanne Balsom, who raised Natalie. Natalie also blindsided Jessica when she revealed Seth was her boyfriend and had been working with Natalie to get close to Jessica and gain access to Llanfair. When a DNA test proved Natalie's claims, Jessica was devastated. She was furious with Seth, and horrified to meet her supposed birth mother, Roxanne, a foul mouthed alcoholic.
A presumed dead Mitch Laurence returned to Llanview and dropped another bombshell: he was Jessica's father. Mitch revealed that years earlier, he had drugged and raped Viki, and when she gave birth she gave birth to twins (Jessica and Natalie) with different fathers (Jessica was Mitch's, Natalie was Clint's). Mitch had Natalie whisked away to Roxanne and her husband (Mitch's accomplice) home where she was raised, while Jessica was raised in the comforts of Viki's posh home.
Natalie Vega was born to Clint and Viki Buchanan along with her half-sister, Jessica. Jessica's father, Mitch Laurence (who had secretly raped Viki, information that did not get out for years), had no use for Natalie (Clint's daughter) and shipped her off to live with his co-hort, Dr. Balsom. Balsom died and Natalie was left to be raised by his widow, the alcoholic Roxanne, who paid little attention to Natalie or her son Rex. Rex was sent away to live with his aunt at an early age. Natalie grew up believing Roxanne, who was neglectful and verbally abusive, was really her mother. Viki and Clint, meanwhile, believed that Jessica was their only child (Clint wasn't present for Natalie's birth, during which Viki had reverted to her other personality, Niki Smith).

Allison Perkins, a disciple of Mitch's who kidnapped the infant Jessica, contacted Natalie and told her the truth about her parentage. Realizing everything she had been deprived of by not being raised as a Buchanan, Natalie came to Llanview with her boyfriend Seth determined to get her share of the Buchanan fortune. She planned to split her share of the money with Allison.

Natalie pretended to befriend Jessica while Seth "romanced" her, all in an effort to gain access to Llanfair, Jessica's home. Stealing an item of Viki's, Natalie had a DNA test performed and revealed herself as Viki's true daughter. Allison, backing Natalie up, claimed the baby that she kidnapped as an infant was really Natalie and the baby returned was Jessica. The disbelieving Buchanans ordered another DNA test, which proved Natalie's claim. Viki and her family were forced to accept the abrasive Natalie, who slowly started to build a relationship with her biological mother.

Seth, feeling guilty over his many lies to Jessica, began to develop feelings for her. Natalie was not happy with this, and set out to keep the two away from each other. She made many attempts to cast Seth in a bad light, such as framing him for stealing from Break Bar. After catching Al Buchanan walking (he was faking a paralysis) she blackmailed him into helping her keep Seth and Jessica apart. During this time Natalie grew close to Cristian Vega. The animosity between Jessica and Natalie continued and after an argument Natalie accidentally pushed Jessica through a banister.

Natalie realized Seth loved Jessica and began to reform her manipulative ways, which started with her telling Cristian that Al faked his paralysis, freeing Cristian to be with Al's wife Jen. As Cristian and Natalie's friendship deepened, the two began to develop feelings for each other.

Niki Smith, one of Viki's alternate personalities, resurfaced and began to alienate Natalie. Niki wanted to be clear of Viki's familial obligations and started to gaslight Natalie into making her believe that she had Dissociative Identity Disorder and had pushed Viki's husband Ben out a window. Al took advantage of this opportunity to make Jen believe that Cristian and Natalie's friendship had developed into something more. Al set fire to Jen's room and framed Natalie, blaming it on her "blackouts."