Hi, just saw your question on genu varum,or in simple terms your sons knees are closer than they should be and the legs are curved or bowed .Sure your child will be able to walk ,at 18 months he will be already toddling around .i suggest that you and your baby have an X-ray of the knees done before he is 2 years of age to see if the upper part of the shin bone is projecting inwards .causing the bowing .If it is so then see an orthopec surgeon.this is called Blounts disease and will need some corrective appliances. Also check out if there are evidences of rickets or vitamin D deficiency ,in this case supplementation with Vit D will bring it back to normal. though most children till 3 years have bowing to some degree better to check out treatable and correctable conditions earlier .