Laura Blankman, the Montgomery County police officer who is seeking permanent custody of Cornilous Pixley, said yesterday that she considers herself to be the 3-year-old's "psychological" mother in testimony that offered a glimpse into the conflicted world of a boy who has spent his whole life with two "mommies."

Blankman took the stand in her second Circuit Court trial to gain custody of the little boy whose biological mother, Latrena Pixley, pleaded guilty to smothering her 6-week-old daughter to death during what a psychiatrist said was postpartum depression at her District home in 1992.

Pixley, 26, who is seeking to regain custody of Cornilous, watched quietly yesterday as Blankman, 29, described the little boy's life in suburban Montgomery County, where she said he is an inquisitive, playful child who attends preschool and loves putting on his toy tool belt to go "help" a neighbor work on projects around the house. His friends have affectionately nicknamed him "Corny," and he will turn 4 next month.

"We have a very loving, caring relationship," Blankman testified in response to questions from Nancy Poster, one of her attorneys, "what I perceive as a typical mother-child relationship."

Yet she also talked about the conflict that is becoming all the more apparent to him as Cornilous grows up--the fact that he has two women who want to be his mother. And on cross-examination, when Pixley's attorney, Ralph Hall Jr., asked whether she considers herself his mother, Blankman said: "I believe I'm Cornilous's psychological mother, yes. . . . I could never be his biological mother."

Every Friday evening, the little boy leaves his home with Blankman and is taken to Pixley's home, returning on Saturday afternoon. Blankman said she is sometimes concerned about his outlook when he returns from those visits. "It seems like Cornilous is confused," she said. "When he comes home, it just seems like he's falling apart at the seams."

On Monday, a court-appointed psychologist, John B. Mealy, said the conflict between the two women is troubling the child and could lead to future problems if not resolved. "I see there is confusion in him, inner distress at times," he said. He urged the two sides to come to an understanding and said neither woman should be removed from his life.

Mealy said Blankman has indeed become the boy's primary attachment. Because of that, and because of lingering concerns that Pixley might neglect the child, he recommended that Blankman be given custody, with Pixley maintaining her visitation rights.

Yesterday, Pixley's attorneys raised questions about Cornilous's life with Blankman. During his cross-examination, which is to resume this morning, Hall persistently questioned Blankman about her work schedule as a police officer in the Germantown district, a job in which she often must work weekends and overnight hours and often must rely on babysitters or her mother to care for the child.

He also questioned her about why she has made a series of key decisions about Cornilous's upbringing--such as placing him in preschool, dedicating him at her church and seeking to change his first name to Joshua--without consulting Pixley.

After yesterday's court session, Hall's co-counsel, Jennifer Evans, said those questions were important because Blankman "is not his mother. She does not have guardianship. She only has physical custody."

"I think it's reprehensible. The child's name is not Joshua," she said. On the stand, Blankman said she had sought the name change as part of her bid to legally adopt Cornilous two years ago.

She lost that case, however, when Circuit Court Judge Michael D. Mason ruled that custody should revert to Pixley. That ruling was thrown out by the Court of Appeals earlier this year, setting the stage for this second trial, before Montgomery County Circuit Court Judge Louise G. Scrivener.

Pixley's lawyers said they believed Blankman was putting on a "performance" on the stand. They said she has toned down her testimony since the first trial, and noted that she has received lessons in how to testify in court as part of her training as a police officer.

Evans said they would resume their cross-examination today and attempt "to paint a fuller picture before the court of who is seeking to have custody of this child."

CAPTION: Montgomery County police officer Laura Blankman, left, and her attorney Nancy Poster discuss Blankman's custody battle over Cornilous Pixley, 3.