Perhaps the best description of this children's story is by quoting the summary given:
"At New York City's Central Park Zoo, two male penguins fall in love and start a family by taking turns sitting on an abandoned egg until it hatches." Onc of the authors is Justin Richardson, M.D., who has co-authored, "Everything You Never Wanted Your Kids to Know About Sex (But Were Afraid They'd Ask). Although this is presented as a fictional story, all the events in the story are true. I would say if you were wanting to read to your child about varying 'lifestyles' of families...this book would work.