Answer:
   
   The issue of "clean" and "unclean" usually refers to a discussion of
   the Jewish Laws relating to sexual relations. These laws are known
   collectively as toharat ha'mishpacha, family purity. These rules
   inform us that a women enters the state of "tameh" when she is
   "niddah" (menstruating). During this time the couple must refrain from
   all physical contact, especially sexual relations. After the cessation
   of her menstrual flow, the women counts seven days before immersing
   herself in a mikva, at which time sexual relations between man and
   wife can then continue.
   
   This brings us to the subject of "tahor" and "tameh". Translating them
   as "clean" and "unclean" (or "pure" and "impure") is erroneous. These
   terms actually have nothing to do with physical cleanliness. Rather,
   they describe a state of ritual applicability in regards to fulfilling
   certain mitzvot, such as those associated with the Temple in
   Jerusalem, the cultic function of Kohanim (priests), or sexual
   relations within in a Jewish marriage. Thus, Tahor and Taharah
   actually mean "ritually pure" and Tamae and Tumah mean "ritually
   impure".
   
   Conservative Judaism teaches that the laws of Tohorot HaMishpacha are
   binding. The movement's official stance is defined in detail in Rabbi
   Issac Klein's "A Guide to Jewish Religious Practice". There is one
   notable difference between Orthodox and Conservative Judaism in this
   area: Some Conservative Jews note that the extra waiting period of
   seven days is not a Torah or Talmud requirement. It was initially
   discussed as a custom of the pious, and it was only later that this
   stringency was made mandatory. While the Conservative movement has not
   yet issued an official ruling in this regard, some American
   Conservative halakhic experts have individually written teshuvot
   (responsa) that these extra days are a chumra (stringency) and thus
   not mandatory. Instead, they say that a couple must abstain while a
   woman is niddah, but only have to wait one extra day before immersion
   in a mikveh - not an entire week. These rabbis include Joel Roth,
   Michael Gold, Susan Grossman and Talmud Professor Dr. David C.
   Kraemer. Some good sources on Conservative practice in this area are:
    1. "This is My Beloved, This is My Friend: A Rabbinic Letter on
       Intimate Relations". Rabbi Elliot N. Dorff. The Commission on
       Human Sexuality of the Rabbinical Assembly, 1996. Available from
       the USCJ Book Service.
    2. "Does God Belong in the Bedroom". Rabbi Michael Gold, JPS, 1992.
       Although this book is not an official publication of the
       Conservative movement, its author is a member of the Conservative
       movement's "Commission on Human Sexuality of the Rabbinical
       Assembly", and represents a mainstream Conservative view.
    3. United Synagogue Review, Fall 2001, "Coming of Age: The Growth of
       the Conservative Mikveh Movement"
       [5]http://www.uscj.org/item15_660_666.html
    4. Dipping Into Tradition: The Mikveh Makes a Comeback, JTS Magazine,
       Volume 10, No.3 [6]http://www.jtsa.edu/news/jtsmag/10.3/dip.shtml
    5. Must a women go to the Mikveh after her period? A short responsa
       by Conservative Rabbi Daniel Kohn.
       [7]http://www.jewish.com/askarabbi/askarabbi/askr875.htm
       
   In recent years, there has been some increase in interest among
   younger Reform and Reconstructionist Jews in the area of toharat
   ha'mishpacha, family purity. While until recently the Reform movement
   had been fairly hostile to both the rituals of and philosophy behind
   toharat ha'mishpacha, the last couple of decades have seen a slow but
   steady turn towards traditional practices, often with new
   interpretations. Some of the younger American Reform rabbis are in
   fact moving for the Reform movement to officially reclaim this
   practice in an official manner.