More seriously, are the current dummies sufficient or do they need a wider variety? Will someone 5'2" slide under a seat belt or be hot badly by the air bag? Gender isn't the primary issue. Size is.
Hot->hurt.
Size is not the only consideration. A man and a woman of approximately the same outer dimensions will have other differences, the most notable of which in the context may be bone strength or thickness.
Consider too that older people have less bone mass, so we would need dummies for that situation as well.