Maybe plastic surgery, dermatology, rheumatology, and psychiatry don't, but other doctors are going to be splitting weekends and call among the members of their group. For specialties that have fewer doctors nationwide like vascular surgery, cardiothoracic surgery, and neurosurgery you can expect to be on home-call every third night and covering the weekend every third weekend. You might have to come in to operate every other call, and on the weekend you'll have to round on all of your group's patients on Saturday and Sunday and operate if anything operative comes in.
My sister-in-law is an Ob/Gyn. Yes, there's call, but that gets compensated for by fewer hours during the M-F week. There's a reason why doctors on the golf course on Wednesdays is a cliche.