That's just a saying, baby's are not lazy. On average boys tend to concentrate on gross motor skills earlier than girls so tend to crawl/walk/jump earlier while girls tend to concentrate on communication skills earlier so tend to point, show, talk earlier. There are exceptions to the rule but on average this is how it tends to work.
Hi. I know all babies grow at different pace so no comparison but just wanted to share my baby bog is 7 months and has not started crawling. While my daughter who is 7 years was crawling, pushing, gliding even started walking at 11 months. My sis says boys are lazy ☝🏼😏. How true is this?