Title: List of WTA number 1 ranked singles tennis players
Content:   The WTA Rankings are the Women's Tennis Association's (WTA) merit-based system for determining the rankings in women's tennis. The top-ranked player is the player who, over the previous 52 weeks, has garnered the most ranking points on the WTA Tour. Points are awarded based on how far a player advances in tournaments and the category of those tournaments. The WTA has used a computerized system for determining the rankings since November 3, 1975. Since 1975, 27 women have been ranked No. 1 by the WTA, of which 14 have been year-end No. 1. The current world number one is Ashleigh Barty of Australia.
Title: List of WTA number 1 ranked singles tennis players
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Title: Top ten ranked female tennis players
Content:  This article presents top ten lists of female singles tennis players, as ranked by various official and non-official ranking authorities throughout the history of the sport. The article is split into two sections: 1921–1974, and since 1975 when the first official WTA Rankings were published, for ease of navigation.
Title: List of PSA women's number 1 ranked players
Content:  This article is a list of PSA women's number 1 ranked players in the Official Women's Squash World Ranking. The Official Women's Squash World Ranking are the Professional Squash Association's (PSA) merit-based method for determining the world rankings in women's squash. The top-ranked player is the player who, over the previous 12 months, has garnered the most PSA ranking points. Points are awarded based on how far a player advances in tournaments and the category of those tournaments. The WISPA, the WSA and the PSA has used a computerized system for determining the rankings since April 1984. An updated rankings list is released at the beginning of each month.
Title: List of WTA number 1 ranked singles tennis players
Content:  Current record in bold.
Title: World number 1 ranked female tennis players
Content: The Women's Tennis Association introduced a computerized ranking system in November 1975, which is incorporated into this list. ; The International Tennis Federation's year-end number 1 classification that was introduced in 1978 is no longer named as such, and has evolved into the ITF World Champion designation and award. ; The Women's Tennis Association has awarded a WTA Player of the Year award each year since 1977. World number 1 ranked female tennis players is a year-by-year listing of the female tennis players who were ranked as world No. 1 by various contemporary and modern sources. Notes: 
Title: Top ten ranked female tennis players (1921–1974)
Content:  This article presents top ten lists of female singles tennis players, as ranked by various official and non-official ranking authorities throughout the history of the sport. The article is split into two sections: 1921–1974, and since 1975 when the first official WTA Rankings were published, for ease of navigation.
Title: List of WTA number 1 ranked singles tennis players
Content: Note The rankings are sourced by the WTA Media Guide and the WTA website (which usually revises its rankings every Sunday night or Monday morning, except when tournament finals are postponed). 
Title: Top ten ranked female tennis players
Content:  The official WTA Rankings were introduced in November 1975.
Title: Serena Williams
Content:  Serena Jameka Williams (born September 26, 1981) is an American professional tennis player. She has won 23 Grand Slam singles titles, the most by any player in the Open Era, and the second-most of all time behind Margaret Court (24). The Women's Tennis Association (WTA) ranked her singles world No. 1 on eight separate occasions between 2002 and 2017. On her sixth occasion, she held the ranking for 186 consecutive weeks, tying the record set by Steffi Graf. In total, she has been WTA No. 1 for 319 weeks, which ranks third since WTA Rankings began behind Graf and Martina Navratilova. She is the only American player, male or female, to win more 

Question: who is ranked 1 in women's tennis?
Answer: Simona Halep.