Twin Birth Study Collaborative Group:
Jon F R Barrett, Alexander C Allen, B Anthony Armson, Elizabeth V Asztalos, Scott Farrell, Amiram Gafni, Julia E Hanigsberg, Mary E Hannah, Eileen K Hutton, K S Joseph, Line Leduc, Dalah Mason, Arne Ohlsson, Nanette Okun, Susan Ross, J Johanna Sanchez, Andrew R Willan, Alexander C Allen, B Anthony Armson, Elizabeth V Asztalos, Jon F R Barrett, Michael Bracken, Patricia Crowley, Allan Donner, Lelia Duley, Richard Ehrenkranz, Kevin Thorpe, Jose Luis Castaldi, Marta Susana Bertin, Yamil Partida, Diana Galimberti, Analia Messina, Liliana S Voto, Geraldine N Voto, Marìa Josè Prieto, Fernanda Buraschi, Hèctor Sexer, Mario Palermo, Dolores Montes Varela, Ricardo Savransky, Armando Dunaievsky, Elsa Andina, Cristina Laterra, Sandra Susacasa, Maria Alejandra Frailuna, Silvina Ramirez Almansa, Maria Beatriz Barrere, Horacio García, Mabel Rivero, Elena Elizabet Gomez, Josefina Schinini, Monica Ahlbom, Jesus Daniel Aguirre, Raquel de Lourdes Martín, Arturo Videla, Walter Mesas, Carlos Arias, Maria Cecilia Castagnola, Raul Abalos Gorostiaga, Miguel Curioni, Maria Mohedano, Viviana Dip, Alicia Roque, Esteban Marcos Duhalde, Jodie Dodd, Andrea Deussen, Caroline Crowther, Glenn Gardener, Jackie Chaplin, Danielle Wilkins, Kassam Mahomed, Anne Green, Robert Baade, Mano Haran, Ash Hanafy, Greg Davis, Lynne Roberts, Stephen Tucker, Christine Duncan, David Watson, Annemarie Lawrence, Monika Laubach, Ria Breugelmans, Iracema Calderon, Anice Martins, Claudia Magalhães, Jose Guilherme Cecatti, Fernanda Garanhani Surita, Luiza Rosado, Augusto Cortizo Vidal, Goianice Ribeiro de Souza, Nelson Lourenço Maia Filho, Danielly Scaranello Nunes Santana, Renato Augusto Moreira de Sa, Luciano Marcolino, Caio Coelho Marques, Pedro Luis Zanella, Carla Milan, Márcia Dalmolin Bollis, Gustavo Steibel, Antonio C K Ayub, Simone Moreira, Antonio Carlos Barbosa Lima, Adriana Scavuzzi, Alex Sandro Rolland de Souza, Olimpio Barbosa de Moraes Filho, Simone Angélica Leita Silva Carvalho, Renato Augusto Moreira de Sa, Rita Guerios Bornia, Nancy Ribeiro da Silva, Renato Augusto Moreira de Sa, Renata Spinola, Laudelino Marques Lopes, Nelson Sass, Henri Korkes, Elisa Chalem, Eliana Junko Morita Yokota, Miriam Ribeiro de Faria Silveira, Stephen Wood, Leslie Miller, Lynne McLeod, B Anthony Armson, Cora Fanning, Valerie Mueller, Sandra Gregorovich, Elaine Moore, Robert Gratton, Laura Kennedy, Peter Scheufler, Donna Reid, Stephanie Klam, Rhona Daitchman, Duncan Farquharson, Kristy Harrison, Ramesh Kulkarni, Rhonda Scarfone, Joanne Laplante, George Carson, Suzanne Williams, David Rosman, Debbie Nemtean, Femi Olatunbosun, Kathleen Pierson, Joan Crane, Donna Hutchens, Nanette Okun, Arthur Zaltz, Melissa Brown, Melanie Ornstein, Soraya Visram, Jennifer Bordin, Hiliary Siurna, Shelly Petruskavich, Alain Gagnon, Jennifer M Lee, Ariadna Fernandez, Stephen Kaye, Kelly-Ann Haslauer, Geoffrey Cundiff, Ricardo Gomez, Juan Pedro Kusanovic, Karla Silva Neculman, Luis Leighton Valenzuela, Erika Madariaga Leiva, Juan Guillermo Romo Cabrera, Mónica Molina Ravanal, Rodrigo Schiaffino Orrego, Ratko Matijevic, Ahmad Makhlouf, Osama Saber, Tarek Abdelradey, Fred Kirss, Kristiina Rull, Pille Vaas, Hartmut Hopp, Andreas Nonnenmacher, Silke Michaelis, Uwe Hasbargen, Maria Delius, Aris Antsaklis, Peter Drakakis, Tamás Major, Tünde Bartha, Raed Salim, Linda Harel, Benny Chayen, Sima Siev, Mordechai Hallak, Elad Mei-Dan, Ron Gonen, Leslie Wolff, Oscar Sadan, Dalia Mansour-Schwake, Liana Petchinkin, Marwan Hakim, Yuri Perlitz, Moshe Ben-Ami, Samuel Pansky, Donnette Simms-Stewart, Monifa Wilson, Mazen El-Zibdeh, Lama AlFaris, Marion Heres, Aafje Sluis, Frans J M E Roumen, Jeannine Rinkens, Christine Willekes, Sjaak Alleman, Simone Gordijn van Zandvoort, Martina M Porath, Corine Verhoeven, Ben Willem Mol, Forough Radfar, Sultana Khan, Krzysztof Preis, Malgorzata Swiatkowska-Freund, Grzegorz Krasomski, Marcin Kesiak, Michael Krekora, Katarzyna Zych, Jan Wilczynski, Grzegorz Breborowicz, Anna Dera, Sajjad ur Rahman, Amal Abdullah Al-Jassim, Florin Stamatian, Gabriela Caracostea, Miroslava Gojnic, Amira Fazlagic, Milan Perovic, Brankica Vasiljevic, Toma Stefanovic, Anna Gonce, Sara Herrero Rodriguez, Marta Massanes, Elena Carreras Moratonas, Carlota Rodo Rodriguez, Silvia Arevalo Martinez, Elisa Llurba, Anna Suy Franch, Maria de la Calle, Fernando Dans, Marta Sancha, Sara Lopez, Maria Luisa Canete Palomo, María Dolores Maldonado del Valle, María Nieves Rodríguez Martín, Carolina Lázaro-Carrasco Delgado, María Carmen Jiménez Fournier, Dale Ojutiku, Maxwell Masuku, Kerry Goodsell, Donna Southam, Derek Tuffnell, Tracey Germaine, Rebecca Palethorpe, Diane Farrar, Janet Wright, Hamed Al-Taher, Helen Meehan, Leanne Bricker, Michelle Dower, Gillian Houghton, Angela Pascall, Heather Longworth, Ashis Sau, James Thornton, Joanne Fisher, Mohammed Houda, Andy Simm, George Bugg, Ruta Deshpande, Yvette Davis, Fiona Holloway, George Bugg, Ross Welch, Heidi Hollands, Peter Young, Kim Hinshaw, Amanda Bargh, Dawn Edmundson, Helen Cameron, Justo Alonso, Alfonso Garcia Austt, Alejandra Ortiz, Judith Burgis, Stanette Brown, Anthony Gregg, Kristi Borowski, Diedre Fleener, John Deaver, Melanie Sumersille, Christine Aronoff, Kimberly Bland, Eftichia Kontopoulos, Yvette Rivero, Stuart M Lovett, Shana Zatinsky, Mary Diogo, Dean V Coonrod, Blanca Flor Jimenez, Sunny Chan, Sheila A Hewson, Trinh Hoac, Christine Kowal, Kathryn Mangoff, Sonya Mergler, Michael Shi