Not necessarily. Polyurethane condoms are indeed more likely to break due to the lower elasticity of the material. Their effectiveness is still quite good, though, around 95% if used correctly. Polyisoprene condoms, on the other hand, are as effective as latex condoms and are not more likely to break. On the contrary, they offer the same degree of protection (around 98% if used correctly) as latex condoms whilst enhancing sensations due to their thinner walls.