Synthetic fabrics (typically identified as acrylic, polyester or nylon) are made from petrochemicals. The fabric is made by dissolving a polymer such as methyl acrylate in solvent, then extruding and coagulating the filaments in a solution of the same solvent. Petrochemicals are derived from non-renewable fossil fuels. Processing fossil fuels creates vast carbon dioxide emissions, which are the primary cause of global warming.
Synthetic cloth does not "breathe" - air can only pass through gaps in the fabric. This means that it traps moisture, odour and heat against the skin, yet offers little protection from external cold and rain.
Moisture build-up on the outside of a synthetic garment acts to create a cold layer against the skin.
So when your kids are wearing synthetics they're more likely to sweat, smell and shiver.
Synthetic cloth is inherently flammable (retardant additives must be used).
Synthetic cloth offers no inherent protection from UV rays.
Synthetic cloth is prone to surface pilling and the buildup of static charge.

[click on links for more info]
Merino wool is a natural, biodegradable, made in Australia fibre. It is grown without the extensive use of herbicides and fertilizers. Unlike the non-renewable fossil fuels used to make polyester and other synthetic fibres, wool grows right back, year after year.
Merino 'breathes'. It naturally traps body warmth (even if the garment is wet) creating protection from the cold, yet draws moisture away from the skin to prevent overheating when the wearer is active. When cold moisture is absorbed by a woollen garment, it is warmed by body heat rather than drawn to the skin surface.
Merino naturally expels odour due to its anti-microbial properties.
Merino is naturally fire resistant.
Merino is naturally UV resistant with a minimum UPF of 25.
Fine Merino wool fabric does not prickle and won't make you itchy.
Merino wool can absorb up to a third of its weight in moisture without feeling 'wet', and naturally expels it back into the atmosphere. Because of this, it dries quickly.
The bioelectromagnetic properties of Merino wool are naturally balanced with our own, thus avoiding buildup of static charge.

All wearwoolf garments are MACHINE WASHABLE.