Judge, concurring and dissenting:
I concur in part and dissent in part. Although I agree with the majority as to the voluntary impoverishment issue and the disposition of the issues raised in the cross appeal, I believe the trial court erred or abused its discretion 1) when, on the record before it, the court deviated downward from the child support guidelines because the father now has two young children from a recent marriage; 2) by failing to make the support order retroactive to the date of the mother’s petition for modification; 3) by failing to require the father to contribute to the child’s medical and educational expenses, which were incurred by the mother during the pendency of her petition for modification; and 4) in regard to the amount of money assessed upon the father as a contribution towards Justin’s private school tuition.
I. Child Support
To be sure, I have no quarrel with the general proposition espoused by the majority that “a single child will enjoy the undiluted largess of both of his parents” but “the expectation of the first child is inevitably diminished” when “siblings enter the picture.” I strongly disagree, however, with any suggestion in the majority opinion that the addition of half-siblings “is per se a significant part of the departure rationale.”
*376Clearly, the addition of half-siblings may, in the appropriate case, justify a downward departure from the child support guidelines. F.L. § 12-202(a)(2)(iii)(2). But, it is not an automatic entitlement. The presumptive correctness of the child support guidelines is mandated by statute. See F.L. § 12-202(a)(2)(i). Mere proof that Mr. Fiorenza has two other young children, standing alone, is insufficient to rebut the presumption, and therefore does not warrant a downward departure from the guidelines under F.L. § 12-202(a)(2)(iii)(2). Yet that is how the lower court analyzed the matter, and the majority has sanctioned that approach.
Moreover, F.L. § 12-202(a)(2)(iv)(2)(C) expressly requires the court to make a finding as to how the determination to deviate downward from the guidelines “serves the best interests of the child.” See Tannehill v. Tannehill, 88 Md.App. 4, 15, 591 A.2d 888 (1991) (stating that when the trial court determines that a departure from the guidelines is warranted, the court must make a finding, inter alia, as to how the departure serves the best interests of the children). The lower court’s statement that “it would be in the best interest of Justin that his half-siblings not have to do without (anymore than necessary)” is, in my view, an inadequate explanation as to how the downward departure from the guidelines serves Justin’s best interests.
Additionally, a review of the record does not provide an adequate .evidentiary basis for the trial court’s decision. Although Louis, the father’s youngest child, has health problems due to Louis’s premature birth, the lower court acknowledged that Louis’s medical problems were not “quantified.” Indeed, no evidence was presented as to any out-of-pocket expenses actually incurred by appellee for the care and treatment of Louis. When Mr. Fiorenza was questioned about the health problems of his baby, he conceded that he has health insurance coverage. The following colloquy is relevant from recross examination:
APPELLEE’S COUNSEL: And the medical [expense], $494 a month. Does that include your wife and your new children?
*377MR. FIORENZA: Sure.
APPELLEE’S COUNSEL: And that’s for what exactly?
MR. FIORENZA: That is for medical, dental and vision insurance.
Mrs. Fiorenza also testified at the hearing. In answer to a question about the special needs of Louis, she said: “So far, a lot of it is unknown.” When asked about the health care expenses for the baby, Mrs. Fiorenza said: “At this point, they are unknown. We have the physical therapy and occupational therapy that’s going to happen every week. I mean, down the road, if he has any learning disabilities or anything like that — .” She was again asked about the cost of the baby’s medical care and answered: “At this point, we don’t [know]. I know that insurance does not cover all of it.”
It is equally significant that the court never considered whether Mrs. Fiorenza contributes to the family’s income. The majority has ignored that evidentiary gap, even though it upholds the court’s attribution of $50,000 in income to Justin’s mother, who elected to quit her job in order to attend to Justin, who clearly had emotional difficulties. Moreover, she, too, has a younger child. The trial judge acknowledged that appellant’s decision to quit work appeared to help Justin, and the judge had “some sympathy for [the mother’s] position.” Nevertheless, the court said: “Unfortunately, were we to apply the litmus test, every mother (and some fathers) could stop working because it would be better to raise the children (especially at a younger age). Our world does not permit this. Two income families are the norm, and single parents cannot stay home and take care of the children. We must posit $50,000 to her.” (Emphasis added).
What is good for the goose is good for the gander. Although I agree with the trial court’s determination to attribute $50,000 in income to appellant, and I would not quarrel with Mrs. Fiorenza’s decision to forego a job outside the home in order to maximize her time with her children, I am nonetheless dismayed that the court deviated from the guidelines without considering Mrs. Fiorenza’s financial circumstances. *378If the court felt obliged to attribute income to Ms. Dunlap, even though she no longer works outside the home, the court, at a minimum, ought to have considered whether the mother of Mr. Fiorenza’s two other children contributes to their economic well being.
Evidentiary snippets indicate that Mrs. Fiorenza is an educated woman, and she does, indeed, have a job. Mrs. Fiorenza testified that she is “college educated, I’m a registered nurse.” Moreover, the evidence revealed that she is employed on a part-time basis. At the hearing, Mr. Fiorenza testified that when his wife worked, she earned $25,000 a year. At the time of the hearing, he said: “She’s working part-time, so it’s considerably less.” Yet, Mr. Fiorenza acknowledged monthly contributions to a mutual fund of $150, made “from my wife’s pay.” Further, he said: “My wife is the one that supplies that fund.”
The court’s decision to deviate from the guidelines is all the more curious in view of the parties’ earnings disparity. The court attributed $50,000 in income to the mother, which she of course does not really earn. On the other hand, the court attributed $62,000 in income to the father, a sum that corresponded to his net taxable business income in 1997. But, appellee’s tax return shows gross business income for 1997 in excess of $88,500. From that sum, appellee deducted over $6,000 in car expenses and claimed an expense of about $9,000 for meals and entertainment. Justin’s needs did not have to be sacrificed in order to maintain the father’s lifestyle.
I also disagree with the majority’s assertion that the “guidelines themselves take cognizance of [the] unavoidable mathematical fact of life” that the presumptive support figure for one child “cannot stand undisturbed” when siblings are involved. The majority overlooks that the guidelines refer to multiple children in the same household, and obviously take into account certain economies of scale inherent in having more than one child in the home. When a family has one child, the family needs a place to live, including a bedroom for the child. In a family with three children, however, the family *379might well make do in the same living space, by having the children share the bedroom and bathroom. Other costs, such as utilities, are also largely fixed, regardless of whether there is one child or more than one in the home. Moreover, in the examples posited by the majority, although Justin’s share of the overall child support declines as the number of children in the home increases, the total child support available to the custodial parent increases with every additional child.
In sum, the father had the burden to rebut the presumption that the guidelines amount of support was correct. Merely having two other children is not enough to rebut the presumption. I agree with appellant that “if a downward deviation was appropriate in every case where there are subsequent children born to a party, the legislature would have provided for same in the same manner that the guidelines allow a parent to deduct pre-existing child support.” Moreover, the suggestion of the majority that the court did not abuse its discretion because the father suffered an overall increase in his child support obligation is surely not the test of whether the court abused its discretion.
II. Retroactivity and III. Post Petition Expenses
In my view, the trial court abused its discretion in failing to make the child support order retroactive to the date of the mother’s filing of her petition in September 1997. See F.L. § 12-104(b). At that time, the mother sought an increase in child support and contribution for medical and tuition expenses incurred during the 1997-1998 school year. I also believe the trial court erred when it failed to award any reimbursement to the mother for medical expenses, and abused its discretion by failing to assess the father for the additional tuition costs incurred while the petition was pending.
The evidence showed that, as of September 30, 1997, there was a remaining balance of $980 for Justin’s orthodontic *380expenses. In addition, the evidence showed that, subsequent to filing her petition, appellant paid Dr. Robert Marcus $950 for mental health counseling for Justin. Prior to filing the petition, the mother had consulted with Dr. Harold Levinson in New York in connection with Justin’s attention deficit hyperactivity disorder, and that doctor scheduled a re-evaluation of Justin for a month following the hearing. The mother estimated that medical visit would cost over $800, and it would not be covered by insurance. In addition, the mother paid Justin’s monthly health insurance premium. She also incurred tutoring expenses of over $1,000 for Justin during the Fall 1997 semester. During the 1997-1998 school year, Justin was enrolled at Queen Anne’s School, and tuition payments for that year amounted to $9,300, which the mother also paid. At the time of the hearing, appellee was paying just $200 in monthly child support and $200 a month toward Justin’s tuition. Notwithstanding the size of Justin’s medical and tuition bills during the relevant period, and their necessity, the court did not require appellee to contribute a single cent.
F.L. § 12-204(h) provides:
Extraordinary medical expenses. — Any extraordinary medical expenses incurred on behalf of a child shall be added to the basic child support obligation and shall be divided between the parents in proportion to their adjusted actual incomes.
(Emphasis added). Further, F.L. § 12-201 (h)(1) defines “extraordinary medical expenses” as “uninsured expenses over $100 for a single illness or condition.” F.L. § 12-201(h)(2) expressly includes “uninsured, reasonable, and necessary costs for orthodontia, ... and professional counseling or psychiatric therapy for diagnosed mental disorders” as extraordinary medical expenses.
In Boswell v. Boswell, 118 Md.App. 1, 34-35, 701 A.2d 1153 (1997), aff'd., 352 Md. 204, 721 A.2d 662 (1998), we reversed the circuit court because it ordered the father to shoulder the cost of all unreimbursed medical expenses for the children. Writing for the Court, Judge Davis said that “the circuit court *381erred by ordering [the father] to pay all unreimbursed medical expenses for the children rather than split the cost of those expenses according to income.” Id. at 34, 701 A.2d 1153. Here, the court departed downward from the guidelines to reduce the father’s monthly child support obligation, and then did not require the father to pay any amount towards legitimate and undisputed medical expenses incurred while the petition for modification was pending.
Moreover, I believe the court abused its discretion by failing to assess the father for any portion of the hefty tuition that was incurred on Justin’s behalf in the 1997-1998 school year. Clearly, the mother made a desperate attempt to find a suitable school placement for a troubled child. The court agreed with that decision, saying “it appears to be the only answer.” In the face of that finding, I believe the court should have exacted a contribution from appellee towards the expense.
In sum, at the time of the hearing, although appellant was unemployed, she was paying all of Justin’s medical and orthodontic bills and all but $2,400 of his tuition costs. Appellee, on the other hand, was paying $200 per month in child support and $2,400 per year towards Justin’s tuition. On this record, I believe the trial court erred by failing to make child support retroactive to the date of filing of appellant’s petition, and by failing to order the father to pay any of the health care expenses incurred after the petition was filed. Under the facts attendant here, the court also abused its discretion in not requiring the father to contribute to the tuition expense for the 1997-1998 school year. As appellant aptly points out: “The irony is that [the father] spent over $11,000 in attorney’s fees in this case seeking custody of Justin and more involvement in Justin’s life but refused ... to ... share equally in Justin’s financial obligations.” In its ruling, the majority has condoned that conduct.
IV. Private School Tuition
I am further of the view that the court abused its discretion in the way in which it allocated the cost of prospective private *382school tuition. As noted, the court acknowledged that Queen Anne’s School “appears to be the only answer” for Justin. Yet, after failing to require the father to make retroactive child support payments, and after excusing the father from contributing to substantial medical and tuition expenses incurred by the mother for Justin after her petition was filed, and after departing downward from the statutory child support obligation, the court assessed the father only $300 per month, or $3,600 per year, towards a tuition expense of approximately $10,000 per year.
The majority seems to believe that the $300 per month contribution from the father towards tuition was appropriate, because Mr. Fiorenza was subjected to an increase in his monthly child support payment, from $200 to $400, and, coupled with the $300 monthly tuition payment, he is now shouldering a monthly obligation of $700 for Justin. Unfortunately, as the majority notes, Justin is no longer at Queen Anne’s School. The reason is obvious. Justin has been forced to leave the only school where he has enjoyed success, because his mother was unable to continue to pay most of the tuition expense, along with all the other expenses the court required her to assume.
The result in this case is unconscionable, and I therefore dissent.