Whether you have a sister or not, it’s a relationship that has long fascinated us. In this special edition of Woman’s Hour, Nuala McGovern explores what makes the female sibling dynamic so compelling.If you were watching the Paris Olympics, you might have spotted identical twins Lina and Laviai Nielsen taking to the track. The Olympic duo join Nuala to discuss competing together at an elite level in athletics, winning bronze side-by-side for Team GB, and navigating triumphs and challenges in the public eye after Lina’s Multiple Sclerosis diagnosis.Psychotherapist Jennifer Gledhill joins Nuala to talk about the psychology of sister relationships. What pushes you apart, and what brings you together? She also gives her tips on how to have a better relationship with your sister.How do you deal with the grief of losing a sister? British-Kurdish activist Payzee Mahmod’s joins Nuala to talk about her beloved sister Banaz, who was murdered aged 20 in a so-called 'honour' killing. Their father and uncle are serving life sentences for the murder. Nuala and Payzee talk about loss, legacy and how Banaz’s death drove Payzee’s campaign against child marriage.What is Nuala like as a sister? Joining us from Ireland to spill the beans are Nuala’s own two sisters – Vera and Eileen!Film historian Alex Von Tunzelmann charts one of the most famous sisterly feuds in Hollywood history – the explosive rivalry between the Oscar-winning British actresses, Olivia de Havilland and Joan Fontaine.And what if you don’t have biological sisters or didn’t grow up with them, but want the support system that can come with a sisterhood? Angel, from London, is now 21 years old and was in the care system from the age of five. She’s a mentor and ‘big sister’ for Sister System, a charity that works with care-experienced women and girls. Angel and the charity’s founder Okela Douglas join Nuala to discuss why sisterhood can have such a profound impact.Presenter: Nuala McGovern Producers: Maryam Maruf and Erin Downes Editor: Olivia Bolton Studio Manager: Gayl GordonArchive: Fleabag / Two Brothers Pictures / Harry Bradbeer; Pride and Prejudice / Working Title Films / Joe Wright; Little Women / Columbia Pictures / Greta GerwigThe book reading is from Joan Fontaine’s memoir, No Bed of Roses published by William Morrow and Company