(Minneapolis, MN) -- Minnesota-based Target Corporation says it will begin using gender-neutral signs in its children's product areas. A tweet showing a sign distinguishing between "building sets" and "girls' building sets" went viral on social media earlier this summer. Even without the formal declaration, industry experts say the change had already started at many major big-box retailers. Target says the changes will be phased in over the next few months. It won't be reflected on the way items are offered on Target-dot-com, where gender is often used as a search term.