I contacted Tupperware Australia via their website, and they gave me the following answer:
There are 2 groups of substances in relation to ‘estrogens-mimicking’ effects (i.e. they stimulate and/or mimic the effect of real estrogens) – they are Bisphenol A and Phthalates. Phthalates are used as plasticizers in PVC – a material not used by Tupperware. Bisphenol A (BPA) is one of the starting substances to make Polycarbonate. Regulatory bodies have put strict limits on the amount of BPA that can be used, and Tupperware Polycarbonate meets these limits by a very large margin and therefore, is not a safety issue.
Petra, for your further information - all plastic raw materials and additives used in the manufacture of Tupperware food storage, preparation and serving products sold in the United State and around the world, meet the requirements in the Regulations of the Food and Drug Administration. All colorants in those products are registered on the French Positive List, which is the most stringent in the world, and comply with the requirements of the Council of Europe Committee of Ministers Resolution.
Now I still don't know if they used BPA in the past and in the products I asked them about. But I found this list on the “The Daily Green” website of Tupperware products that use polycarbonates (BPA) :
Rock 'N Serve microwave line, the Meals-in-Minutes Microsteamer, the "Elegant" Serving Line, the TupperCare baby bottle, the Pizza Keep' N Heat container, and the Table Collection.
Luckily none of the products I got are listed so I can continue using them!