Gillian Marchenko is a Christian, wife, mother, writer, speaker, and advocate for individuals with special needs. She writes and speaks about parenting kids with Down syndrome, imperfect faith, depression, and adoption. She holds a Bachelors of Arts degree in Communications with an emphasis on writing from Moody Bible Institute and belonged to Story Studio's advanced memoir class in Chicago for three years.

She is the author of Sun Shine Down. Her writing has also appeared in Today's Christian Woman, Thriving Family, Connections Magazine, Gifted for Leadership, Fulfill Blog, MomSense Magazine, Literary Mama, Chicago Parent, Charlottesville Family, Chicago Special Parent, EFCA Today, Four Cornered Universe, and the Tri-City Record. Gillian, her husband Sergei,  and their four daughters live in Chicago.